Overview
She is burst type hero that can melt tanks easily but when enemy has too much cc and burst damage she can also playable with sustain build.
Strengths
High damage when combined with starlium scythe because Karina's passive and starlium scythe passive.
Weaknesses
Weak against burst type hero and cc heroes like saber, fredrinn etc.
Damage
High damage potential with survivability chance.
Mage emblem
She can clear jungle creeps fast because of her passive so it is better to maximize her damage and mobility.
Battle Spell
Playing her as a jungler is always a better option due to flame retribution passive.
Early-Mid game(if played well)
It is better to finish enemies first that deals the damage.
Best With Tigreal
Since Karina's second skill can do AOE damage and has high potential to finish off the enemies easily it is the perfect match.
Watch Out For Fredrinn
Fredrinn has a lot CC so it is better to ban him in ranked matches.