I would consider this an Easy match-up for Camille. Could be a little rough right now because of Sion's power in current patches.
*Patch 8.6 Introduced a new rune for bruisers called "Conqueror" Don't have enough experience with this rune or any data to place it in the guides, you'll have to try it out yourself and see how it works*
- Arcane Comet Although many would way this rune is the main reason Camille is meta right now, I wouldn't necessarily pick it over something else. The poke it provides will not help versus Sion because of his W shield and he's going to out poke you by spamming E with Comet. Definitely a bad decision.
- Aftershock This is a very strong rune that may help you versus an unskilled Sion. Resistances it gives will block at least his E damage (maxed spell) because he needs to apply slow with it to land his Q on you. A great choice when you have one or no tanks at all in team.
- Phase Rush Phase Rush is my personal favorite. It's basically a strong counter to Sion. What he wants to do when you engage is E you and start up his Q while you're slowed to land an easy high dmg stun ability. Thanks to Phase Rush you can just run around him avoiding all his main damage. Sion haven't got much to offer besides his Q so any longer fight is better for Camille.
- Electrocute I have no opinion on this rune. Haven't tried it in this matchup, I didn't even consider taking it because of it's burst nature. The only time you would want to take it is when your enemies are all squishy targets and you want to snowball really fast. Definitely not helpful in lane.
- Summon Aery I just started testing this rune, it seems like it can do more damage than Comet during an all in(needs 3 procs for it) but I'd take Phase Rush to all in Sion purely because you want to dodge his Q.
ALSO IMPORTANT TO REMEMBER RUNES ARE OFTEN A PREFERENCE CHOICE BECAUSE ALL OF THEM OFFER DIFFERENT PLAYSTYLES SO DIFFERENT RUNES MAY SUIT DIFFERENT PLAYERS BETTER
Some things to look out for:
- Sion has a huge poke potential so try to dodge his E (it's hard)
- All in may be a good decision since staying in lane for too long is going to get punished by his E-max poke nowadays.
- Try to not fight in big minion waves (6+ minions) since fights with tanks are usually long, you don't want that constant dps bonus for Sion.
- You need to get a good feeling of this matchup since it's pretty all in dependent, you need to know when he's too tanky to kill and when you're able to kill him with an all in. (look out for his items and learn your limits)
If you're playing Phase Rush (which I REALLY recommend) your lane is going to look very aggressive. Remember to always dodge his Q with your proc of Phase Rush like in this clips:
You can also stop his Q with your Ultimate (because it interrupts channels) but Sion's Q goes on half the cooldown instead when interrupted. Like here:
First you need to look at your options: note I'm not telling you to buy this items yet!
- Ninja Tabi
- Tiamat
- Phage
- Sheen
So about Ninja Tabi. I wouldn't ever recommend building this versus Sion, especially as first item. If enemy team has strongly AA focused champions then consider buying it later. If not then opt into Merc Trades instead.
Tiamat is definitely a good buy if Sion is too tanky for you to kill him in lane, go for Tiamat and focus on roaming to mid/jungle instead. Also helps versus his super strong wave clear.
Sheen is great for short trades which you want to do often (as in the clips showed above). An excellent first buy if you're not strongly ahead.
Phage is going to help you all in thanks to the movement speed enabling you to stick close to your enemy for a long time. Get this first if you managed to get a good cs lead/early kill.
Sion may get pretty strong after getting Tabi and Thronmail. You can still shut him down easily thanks to your true dmg on Q. Try to split push against him and play like a little dog that walks up bites and runs away. I know this sounds funny but that's how you do it.
Use first Q on minions, time your E to hit him with true dmg Q, run away hitting him with W so he doesn't follow you and you proc your Phase Rush. note, try to not make an AA reset because you will not convert your bonus damage from Trinity Force to true dmg since it will waste with your first AA instead of using it with Q2