Soulscourge

A whip is not a weapon you swap to, it is how you aim your minions. Each crack marks whatever it touches, your summons drop what they were doing and pile onto that target, and every hit they land carries a bonus while the mark holds. The loop is simple: keep cracking the thing you want dead and let the minions supply the damage.

Catching several enemies in one swing costs you damage on everything past the first, so despite the reach this is a single target tool. It also puts you close enough to be hit back, which is the real cost early on when you have almost no defense.

The Crimson gets a near identical whip, and the gap between them is small enough that world evil barely changes how a summoner opens.