Hellraiser
Arcane
Not just any kind of true damage but true damage based on enemy max HP (in addition to doing base true damage). Which makes her the only AD carry which can reliably kill tanky champs without being fed as fuck. As long as they don't chain-cc and rape her that is. Plus she can easily mop up all the people running away after/during a team fight with her Q and passive which results in her getting fed more easily.