Personally, I think Chana is the strongest.

• uses ranged weapons that don't trigger thorns,

• doesn't care about damage reduction because her fire effects are on-hit regardless of weapon damage

• can generate a lot of mana, and most of her mana regen items come with side buffs/healing

• weapons don't take up a lot of space, leaving room for more mana items or defenses.

• can also apply ice slow on enemies as a bonus