Status Effects
There is currently a Status effect called Bleeding. Its inflicted via Bow with a 10% Chance to add the Status Debuff to the enemy.
Knockback
There are various ways to Inflict Knockback.
Normal Bow Shot and Multi Shot can Inflict Knockback.
Hammer
Stamina/Mana
Like you the Enemys have also Stamina/Mana too.
Its Displayed right under the their Health Bar. They recharge them with normal hits and after time like the Player.
Tactic
When playing Solo its recommended to Pull Mobs one by one.
Getting a Sceptres should be a main Priority for its Healing ability.