Soooo, this is my first guide and it'll be updated quite often since I'm still working out the best tweaks to my playstyle. It's a mix of classic Illaoi meta and my own wacky shenanigans so don't flame my builds and guides too hard.

Stat priorities:

HP
ABILITY HASTE
ATTACK DAMAGE



Item priorities:

HULLBREAKER
FROSTFIRE


Playstyle focuses:

AVOID TEAMMATES
TAUNT ENEMIES INTO E RANGE THEN CHASE THEM DOWN
SAVE ULT FOR 1 V 2+ TO MAX OUT TENTACLE GAINS


Focus on farming minion waves for the first few minutes, warding the jungle and just taunting with E near your tentacles. Don't risk engaging until you have both E and W available (and two tentacles in range). Getting gold is super important, and you don't want to back until you can afford the Steelcaps.

After your first back it's probably fine to just teleport straight back to your turret; I tend to find the cool down isn't an issue early game since nothing much happens. At this point you should be able to engage more with the enemy, though keep an eye out for their jungler since ganks can set you back a lot.

As the game starts to heat up, focus on throwing out that E and destroying the spirit so that the enemy gets weakened.

Start buying components towards Hullbreaker as this item is crucial for getting ahead when focuising on a solo push. With your enhanced large minions it becomes child's play to take a turrent once the plating falls (coupled with the demolish rune). Diving is risky unless your Flash is available or you know for certain you can finish off both the tower and the enemy without dying.

My favourite part of playing split Illaoi comes when she's built up massive HP and has Thornmail, as this is the point where you want to be drawing out multiple enemy champs as you can. Hitting the biggest threat with your E then using R to hit the spirit and enemies at once is a killer move, as this will spawn multiple tentacles and cut your W cooldown in half (meaning spam W for maximum smash!). I've hit a couple triple/quadra kills this way while the rest of my team charged mid and took full advantage of the lack of resistance.