Marmu

Behaviour and Tactics
Marmu has only one attack, curling into a ball and hurling themselves at at The Knight from various angles. Hitting Marmu will knock them back a bit. Staying underneath and attacking upward to juggle them is a dependable method of attack, especially with Quick Slash equipped.

Since Marmu usually stays relatively close to the player, an area of effect build can be quite useful. Equipping Thorns of Agony, Spore Shroom, Grubsong, Quick Focus, and Stalwart Shell helps greatly.

It's recommended to stick to a corner while fighting Marmu. This will limit the angles from which they can attack, allowing for easier defending. Being backed into a corner is not an issue, since any successful attack on Marmu knocks them backwards.

Trivia

 * Marmu appears to be a Puss Moth Caterpillar; as seen here
 * Marmu is most likely the protector of the Queen's Gardens, and died in battle when the Traitor Lord and his followers invaded.

Марму