The Nearby Enemies Killed by anyone count as being Killed by you instead modifier causes Minions, Party members, Allies (e.g. Einhar), Traps, Mines, Mirages, Totems and other friendly entities to attribute their kills to you, letting you fully benefit from modifiers that require Kills.
Ally refers to any creature on the player’s side. They are subject to effects granted by equipment and skills, which have in their description “grants (effect) to you and your allies”. Allies include: