The girl who became a Blood Demon for love.
Each time Carmilla deals damage to an enemy hero, she steals 7-11 Physical & Magic Defense (scales with level) from them. The stolen Physical & Magic Defense can stack up to 5 times and lasts 5s. However, Carmilla can only steal defense from the same enemy hero once every 3s.
Carmilla counters melee Fighters with low durability, such as Dyrroth and Lapu-Lapu, because she can rapidly steal their Defenses with her 1st Skill and Passive while healing herself.
Carmilla is countered by heroes that can ignore or remove her CC, such as Hanabi and Wanwan, since they can't be locked down by Carmilla's 2nd Skill or Ultimate.