At Asgard the whole guild can raid Osh the Eternal Keeper every week. It's always fun to fight a big BOSS in a game. There is a lot of information about this weekly raid event. Below is a brief summery with in yellow the highlights if you are not the reading type. Also here are some useful links if you want to know more:
Maestro is the big BOSS for the weekly guild raids. From Monday - Thursday you'll fight minions to earn Valor Emblems and boost Guild Morale. If you finish all 9 battles, you will receive weekly quest rewards regardless if you won or lost. So participating is always to your own benefit. The more damage the guild does to the minions, the higher Guild Morale will become, which in turn will boost our damage against Maestro. The Valor Emblems are used to buy buffs from the Realm Traveler to fight Maestro with. (You can also buy buffs with gold, but that's for fighting the level 150-160 Maestro. Feel free to get them, but you don't need to waste your gold here.)
Good Buffs (in order):
At the Speed of Light, if you can swap between realms faster Harbinger's Barrier and Requiem will not be able to charge up as much. Especially important when fighting on auto.
Secret Weapon, you'll be able to get rid of the debuff of Enervating Motif more easily.
Strength in Perseverance, you'll be able to get rid of the stun effect of Deafening Motif more easily.
Effective Tactics, the initial damage reduction of Harbinger's Barrier is reduced.
Through a Prism, when interrupting any of the Motifs your heroes will receive a speed buff.
At the Limit, basic attacks in the material world will heal the heroes.
Unbridled Energy, when stepping into material world heroes will receive bonus energy.
Pillar of Confidence, Harbinger's Barrier will take a few seconds longer to fully charge.
The Tireless, Requiem will take a few seconds longer to fully charge.
Power over Life, when stepping into material world your heroes will receive some of the healing blocked by Requiem.
The Healer's Gift, when stepping into material world the heroes will get a boost to healing received for a few seconds.
Okay Buffs:
Vector of Might, control effects that would be applied to Maestro are applied to the Harp instead, thus removing Enervating Motif a bit faster. Note, not always available!
Reverie Given Form, when stepping into the material world your heroes will have the Harbinger's Barrier applied to them for a few seconds.
Perfect Storm, when stepping between worlds incoming damage is reduced for a few seconds.
Charmer's Skill, the initial healing reduction of Requiem is reduced.
The Chosen Protector, Retribution protection, it forces Maestro to hit the tank with his auto attacks instead of the hero that did most damage. Note: not always available!
Crappy Buffs:
There is not a single buff that's completely useless, just some that are less useful.
This team or the variation using Lara instead of Jhu still works against Maestro, but it'll do just barely over 10 million damage. Lara does a bit better than Jhu because she adds more and more buffs during the boss battle and she stands behind Sebastian in the 4th spot, so she isn't effected by the group stun effect.
Far more effective is using the new core of Dorian + Augustus + Orion.
Add some more healing & damage from Celeste and Rufus with an armour buff & magic absorbing shield to finish. But of course there are viable alternatives for the final two slots, for example Thea and Amira.
Another very effective core is Aidan + Morrigan + Corvus. The other 2 heroes you want standing between the two undead, which limits your options. The Lyria & Mushy variation seems to be most effective so far. With Lyria doing some damage and aiding Corvus with buffs plus vampirism. Whereas Mushy is doing quite a lot of damage with her army of spores and she adds an extra armour buff.
Gold Buffs (in order):
Power Unleashed, 25% more magic damage to Hands.
Total Elimination, 25% more pure damage to Hands.
Mischievous Team, 25% increased Pet power.
Sparkling Mood, 25% increased Pet Patronage power.
Keepers of Balance, 25% healing entering the material world.
All the gold buffs are good, but you really only start needing them from the level 150 Maestro onwards. Killing level 160 without them is really hard, even close to impossible at the beginning.
For now spend your gold on boosting the Titan Seal Artifacts instead, it's a far better use of your money.
PS Although the effects of all the buffs are accurate, their order of importance is mostly based on my own findings as available data in regards to Maestro is still limited.
On Friday - Sunday we get to fight the actual BOSS. If you kill one another one will spawn (mostly a stronger one), so everybody get's to join the fun. You have 5 attempts to do damage and each hero can only fight once. Same as with the minions, there are weekly quest rewards for fighting Maestro. So regardless of how little damage your heroes are doing, you should use up all 5 attempts every week.
Maestro uses 6 skills of which only 3 really matter:
Retribution, Maestro uses its basic attacks against the hero that dealt it the most damage since the last use of Retribution. In the Material world, attacks deal physical damage. In the Astral world, they deal magical damage.
Harbinger's Barrier, in the material world, there is a barrier around Maestro: it blocks 20% of incoming damage. With each passing second, the barrier’s strength increases, up to 100%. When a transition from one world to the other occurs, the barrier’s strength is reset to its initial value.
Musical Staves, Maestro uses sound vibrations to deal massive damage in several bars. In the material world, this ability deals physical damage. In the astral world, it deals magical damage.
Deafening Motif, Maestro summons a Thundering Horn that can only be attacked in the astral world. The Horn plays the Deafening Motif, inflicting Stun and Damage over Time on the three closest heroes. The effect lasts until the affected heroes receive appropriate healing.
Enervating Motif, Maestro summons an Exhausting Harp that can only be attacked in the astral world. The Harp plays the Enervating Motif, inflicting an effect that drains heroes’ main stats until they reach zero. The effect lasts until the Harp is affected by at least 5 control effects.
Requiem, in the astral world, Maestro assumes its true form, which is impervious to physical damage. All heroes suffer the Requiem effect, reducing the effectiveness of their healing by 20%. Requiem’s strength gradually increases all the way to 100%. In this form, the Maestro has additional hands that can be targeted by area damage abilities.
Now the skills that don't matter much are Retribution, Harbinger's Barrier and Requiem. It's not that they don't have much effect, but that they are unavoidable. All we can do is get the proper buffs from the Realm Traveler. Just check the Good Buffs list and you'll be fine.
To deal with Musical Staves you'd need heroes with an armour artifact buff and magic defense artifact buff or just power through it with healing. In the material world when you see Maestro use this skill activate the armour artifact buff, in the astral world it's the same with the magic defense artifact buff.
If your heroes aren't glass cannons and you have some proper healing, it's possible to survive without the artifact buffs.
I'd recommend at least one armour artifact buff though.
For Deafening Motif you'll need healing to cancel the effect. So a healer with group healing like Thea is preferred. Don't forget the three closest heroes are affected, so the healer needs to be in the 4th or 5th team spot.
You can also use Sebastian to cancel most of it's effects, but you can only use him once. Keep in mind physical attacks are less effective against Maestro and magic can't crit. So other than preventing the stun Sebastian is of limited use.
Some of the Realm Traveler buffs can also help, both to lessen the healing required and to assist in healing.
And finally to deal with Enervating Motif you'll need control effects. This means bringing heroes who can stun, blind, silence, slow, charm and/or paralyse (there might be other debuffs that also count). The only other way to stop it is by killing the Harp.
The Thundering Horn plays the Deafening Motif, inflicting Stun and Damage over Time on the three closest heroes. The effect lasts until the affected heroes receive appropriate healing.
So make sure you have an group healer like Thea, Martha or Aidan in the 4th or 5th slot to remove the stun effects easily. It also helps if you've already bought the Strength in Perseverance buff, which reduces the amount of healing needed to remove the stun effects. And the Through a Prism buff will speed up your heroes when the Motif is removed.
Other than that it's a fairly easy mini boss.
The Exhausting Harp plays the Enervating Motif, inflicting an effect that drains heroes’ main stats until they reach zero. The effect lasts until the Harp is affected by at least 5 control effects.
So make sure to bring some heroes who can stun, blind, silence, slow, charm and/or paralyse (there might be other debuffs that will count as well). It also helps if you've already bought the Secret Weapon buff, which reduces the number of control effects needed to remove the drain effect. And the Through a Prism buff will speed up your heroes when the Motif is removed.
Other than that it's a fairly easy mini boss.
The Forelorn is able to shift between worlds, because the fabric between the realities has worn thin in this place. Heroes may move to the astral world with a special ability. In the material world, the enemies are protected by the Harbinger’s Barrier: it reduces all incoming damage and gets stronger with each passing second, forcing the heroes to step into the astral plane. In the astral world, the Barrier cannot exist, but physical attacks deal no damage at all, and wounds are harder to heal under the effect of Requiem. Furthermore, The Forelorn is not alone, but acts in a team with Aurora, Yasmine, Maya and Peppy.
Make sure your heroes are able to deal magic and/or pure damage, because you'll want to be able to fight the enemy team in the astral plane as well. Yasmine has powerful poison, so bring Celeste to cleanse it if possible. The other three all have control effects, so bringing Sebastian and using Khorus as main pet are advisable. Toss in a tank and a couple of damage dealers and you're good to go. Most of the recommended Good and Gold Buffs will make this battle even easier, but it's not that hard to begin with.
Osh is the big BOSS for the weekly guild raids. From Monday - Thursday you'll fight minions to earn Valor Emblems and boost Guild Morale. If you finish all 9 battles, you will receive weekly quest rewards regardless if you won or lost. So participating is always to your own benefit. The more damage the guild does to the minions, the higher Guild Morale will become, which in turn will boost our damage against Osh. The Valor Emblems are used to buy buffs from the Realm Traveler to fight Osh with. (You can also buy buffs with gold, but that's for fighting the level 150-160 Osh. Feel free to get them, but you don't need to waste your gold here.)
Good Buffs (in order):
Astral Shield, Wormhole protection, great for that first round and your B-E hero teams.
Sphere Energy Unleashed, more energy means more damage, yes please.
Healing Converter, extra healing becomes more damage.
Chosen by the Stars, more healing after Meteor Shower is always good.
Keeper's Blessing, more stats for the main damage dealer.
Marksman Opportunity, more energy for archers means more damage.
Stellar Tank Resilience, maybe not for your first team, but you will be using tanks.
Okay Buffs:
Immortal Hero, your heroes shouldn't be dying even without this.
Insomnia, there will never be more than 4 nightmares, so there is always one hero left.
Survivor's Willpower, a skill to recover health after you are hit by a nightmare.
Nightmare's Energy, a skill to recover damage after you are hit by a nightmare.
Wakeful Undead, you might actually use this combination of heroes.
Crappy Buffs:
Dreamer's Retaliation, more damage against nightmares (but there shouldn't be any).
Mage's Vigilance, less health for mage nightmares (but there shouldn't be any).
Resilient Grove Keeper, you'll most likely never use this combination of heroes.
Ingenious Engineers, you'll most likely never use this combination of heroes.
This is the easiest team to do most damage against Osh with on auto.
If you have her, using Lara instead of Jhu does even more damage.
Also if your Martha has become too strong, don't use Axel and have her fight without Patronage.
And here is explained how the team works:
Why this team composition is effective against Osh. Or: What is The Best Osh team in Asgard Guild Raid?
If your heroes are dying, swap Albus for Axel to boost healing.
If you're still dying, then double armour buffs should do the trick.
Gold Buffs (in order):
Defense Sphere Override, 15% less damage from spheres.
Defense Sphere Destroyer, 15% more damage to spheres.
Jumpstart, 25% energy right from the start.
Meteors of Haste, +100 speed during Meteors.
Wormhole Suppressor, 15% less damage from the wormhole.
All the gold buffs are good, but you really only start needing them from the level 150 Osh onwards. Killing level 160 without them is really hard, even close to impossible at the beginning.
For now spend your gold on boosting the Titan Seal Artifacts instead, it's a far better use of your money.
On Friday - Sunday we get to fight the actual BOSS. If you kill one another one will spawn (mostly a stronger one), so everybody get's to join the fun. You have 5 attempts to do damage and each hero can only fight once. Same as with the minions, there are weekly quest rewards for fighting Osh. So regardless of how little damage your heroes are doing, you should use up all 5 attempts every week.
Osh uses 5 skills of which only 3 really matter:
Stardome, a bunch of Defense Spheres will float around Osh dealing magic damage to the hero in the front.
Wormhole, the remaining Defense Spheres are absorbed by a wormhole doing massive aoe physical damage.
Meteor Shower, after the wormhole Osh will summon meteors for 5 second doing aoe physical damage.
Planet Parade, all 5 Defense Spheres gather up to do collective damage to the hero in the front.
Nightmare Visions, any Defense Spheres not destroyed during Planet Parade will cause nightmares to spawn on the battlefield.
Now the skills that don't matter are Wormhole and Nightmare Visions. You should be destroying the Defense Spheres so the explosion and nightmares never happen. If they do happen, you should not waste time and recourses to protect yourself against them. You should be using those to raise your dps so you can destroy the Defense Spheres faster.
To deal with Stardome and Planet Parade you need to make sure that whatever hero you have at the most front is able to take the magic damage. This will probably be a tank, but it does not have to be as you can see with Isaac in the best build against Osh.
For the Meteor Shower you want to use an armour artifact buff just before it hits. Most tanks have one, but not all and there are a few others whom have it as well, like Martha our beloved turtle riding healer. You'll also want some aoe healing to get everybody ready for the next round.
Rah-Ozu is quite an easy mini boss. Any decent team will do. Just make sure the tank can take the damage from the Defense Spheres. Having some aoe or splash damage to destroy the orbs helps a lot too.
Basically, just use the standard Osh team.
Noas is a bit more interesting as a mini boss. He attacks the hero furthest in the back dealing a lot of physical damage. If you use Martha (or any other tougher caster) in the back with an Axel patronage
(or any other +armour pet) you'll be able to tank him easily.
He also uses the Defense Spheres and the Wormhole ability so you again need some aoe or splash damage to destroy the orbs. Also grabbing the Astral Shield buff before fighting him makes it even easier.
So once more, just use the standard Osh team.
Merida is the one mini boss that is the most challenging. But the advantage is that she only does
damage to the front hero. So using a proper tank here can make the fight a lot more manageable.
The essence of this battle is speed. You want to kill her before you are overwhelmed by nightmares.
So for example Aurora and Corvus are better tanks here because they also deal damage. For the same reason Celeste or Aiden are better healers than Martha, because she is as slow to start as Josephine.
For the dealers you want strong single target damage. All aoe and splash damage are just a waste of time
in this battle. So for example Jhu is good and Krista or Lars are not. Also be careful when using Yasmine, because she needs to take damage before she starts using her special move.
Be aware of using support (and control) heroes that need time to charge up.
Sebastian starts with almost full energy, so he's good, but most take too long to be useful.
As for the pet, you want to add to damage. So Axel and Olivier are not so good here and Albus is excellent.
Using the standard Osh team here is not recommended.
However if you invested enough into them, you can just overpower her.
By using the rewards obtained at the Asgard Guild Raid you can power up your heroes at the Ascension Spire. You obtain these rewards from killing the minions and Osh. But also from the weekly quests, so make sure to use up all 9 attempts at the minions and 5 attempts at the BOSS even if you're losing, so you at least get the quest rewards.
At the start pick one intelligence based hero (healer or mage), one agility based hero (archer or warrior) and one strength based hero (tank). Focus on increasing just those 3 heroes at first. When you get higher up in their ascension tree and need a different recourse to improve their ascension, you pick a different hero of that type to start anew with the lower ranked resource. In time you'll be leveling up 9 heroes at the same time, 3 of each type with each a different rank of resource.
Now you'll want to use the Ascension Spire a maximum of 3 times each week for the weekly quest rewards and a bit of prestige. Do not power up you heroes more than this. Now why is that? Because these ascension resources are hard to come by and every couple of months there will be the Ascension to Asgard event. To take as much advantage of this event and obtain as many extra resources as possible you'll have to save up between events. So you could even choose to skip these weekly quests altogether. In order to obtain all the extra rewards you'll need to power up your heroes 30 time during this event. This is not an easy thing to do for most players, but try your best and stick to 3 power ups during regular weeks. If you do manage to get the full 30, you'll even earn 5 Eternal Seeds as rewards.
From powering up your heroes at the Ascension Spire you'll obtain Ancient Wisdom Crystals and these in turn can be used to power up different branches of heroes at the Great Tree of Wisdom. At the beginning this is relatively cheap and you'll only be limited by the number of Eternal Seeds you have. Try and get your 10 million damage against Osh every week for the quest reward, because those seeds are hard to come by.
After you have leveled up all branches to level 14 it's time to pick a specialization. Now you have 2 options, boost your favourite hero to the max or pick the branch that'll have the most effect on your overall gameplay. This is a game and it should be fun, so option 1 is a perfectly valid choice. However if you go for option 2 and want to get the most out of that tree, you'll want to level up the Support role branch first.
Why the Support role branch first? Just check out the Osh team and you'll see that 3 out of 5 heroes are supportive types. The stronger they become, the bigger the Osh you can kill and the more resources you will obtain to power up your heroes and so on. Furthermore these 3 heroes and the others from the support branch can be used effectively in all other aspect of the game as well. You'll more often use a hero team that has at least 1 support hero in it than not, especially later in the game. Without them you just aren't that strong.