Dung Defender

Attacks
The Defender does a variety of attacks:
 * Conjures two balls of dung that he throws out after one another that bounce around in the boss arena for a short while
 * Occasionally, he himself will curl into a ball and bounce around, usually along with the two balls of dung
 * He will dive into the ground, move around underground and reemerge, throwing four, smaller balls of dung that break upon impact with the ground of the player
 * Occasionally, he will appear as if he's swimming in dung while he's dived into the ground, emerging occasionally from the ground
 * Once enough damage is done to him, he will do the above attacks in a quicker succession. After this, he will also detect where the player is on the ground when he dives and will try to reemerge close to them.

Tactics
In the beginning of the fight, try to dodge the balls as best as you can. When he stops to conjure the two balls of dung, stand next to him, hit him once, step back when he throws the ball, step forward to hit him again and quickly step back when he throws the second one. This is the safest way to damage him with little risk.

Towards the end of the fight when he does his attacks more frequently, you will notice that he will dive in more often and keep throwing the four balls of dung a lot. Staying right at the left side of the arena is almost completely safe as he will always try to reemerge from the ground close to the player and the balls will just drop on the wall, giving you a safe spot to damage him.

Trivia
From the Kickstarer reveal page:

Deep in the Waterways beneath the City of Tears lurks a shunned being. Once a knight, now lost to puerile obsession: The Dung Defender.

Despite his exile, the Dung Defender has for centuries maintained a self-conferred charge: the protection of his mysterious gleaming 'beloved.'

Stalwart and full of bravado, the Dung defender eagerly challenges all who would enter his noxious realm.