Slivan

Slivan is the final boss of the Escape From Braxis and the Escape From Braxis (Heroic) Brawl.

Background
Slivan the Eternal Mother was one of the primal zerg pack leaders of Zerus who fought for supremacy of the planet, and was an ancient Swarm Host (the boss mercs on Warhead Junction). When Kerrigan infested herself into a primal zerg, Slivan along with other pack leaders rose to kill her and drive the Zerg Swarm off Zerus. With the help of Dehaka, Kerrigan killed Slivan and took her essence, becoming stronger for it.

Opening phase
The first phase will last until the boss has 75% health, upon which it will run away, borrow undergrounds and become invulnerable. During this phase, it will drop some Podlings (which have a delay and a powerful DoT) and cast some poison pools and attack with a somewhat-painful melee attack.

Nydus phase
When the boss skittles off to the northeast corner to rest, it will spawn two waves of 3 Nydus worms, which will each release a hero. Killing the worms will cause the hero to not spawn, but if the worms still have health, the hero will spawn with up to 50% less health. Most teams will not be able to handle 3 enemy heroes at a time, so focus fire down at least one of the Nydus worms.

You will be peppered with mobs, but they aren't so big of a deal, spare only your waveclear spells to stop them from stacking up. The bigger annoyance is the waves of spikes that the boss casts, if you don't notice them, you'll be stunned for a long duration and it could cost you the finishing blow on the Nydus. Make sure you dodge them.

When you finish the first wave of worms and their heroes, the second wave will spawn immediately. This time, you will be harassed by a larger number of mobs, which can cost you some health if they are not managed a little. Now is the time to use your nuke/stim. You can splash 2 worms with one nuke, which will take out half health from each. When the second wave is dead, the boss returns the the center of the arena.

Interlude phase
The boss returns to its opening behaviour. This is a time for you to heal up, before stuff gets serious. Don't bust any ults or items, you don't want to make this part shorter.

Bossfight phase
When the boss gets below 50%, the fight becomes a hectic game of dodge-the-circle. More baneling, more poison pools, more grabs into a spike pool, and constant drops of mobs. Cover for others in this war of attrition. You might want to run from the Podlings, but trigger them first, or your team will attract them all together and be surrounded and busted. Better yet, kill them with your otherwise-useless AOE spells.