Illaoi's core strength relies on landing her E (Spirit Cleave) and utilizing tentacles. Opponents should focus on dodging E and destroying tentacles to minimize her damage.
Recently nerfed, Illaoi is vulnerable when her E is on cooldown or her tentacles are cleared. Champions with high mobility or well-timed ganks can effectively counter her.
Despite her current weakness, a fed Illaoi or one facing melee/engage champions remains a significant threat. Use her ultimate and E combo to dominate area-of-effect teamfights.