Heart of the Swarm Campaign- Zeras: Supreme (Part 3)

Kraith's three attacks are large, but thankfully obvious.  'Many Cuts' is a protracted launching of spines, whose area of effect slowly travels across the ground.  Constant movement will keep your troops out of this, and you can use the opportunity to repeatedly launch Kerrigan's Leaping Strike at the behemoth.  The beast's charging attack is obvious- simply move out of the line of effect, and then be ready to sweep up the primal zerglings that fall from above on the impact.  Finally, the beast has a large area single strike- again, greatly preceded by a target circle that you can simply move out of.  Keep your troops alive and keep Sarah leaping on the pack leader and you will win rather handily.  Make sure to use Mend as needed.

Exit the arena to the Northeast and gather a primal ultralisk to your cause.  From there, it's a Northwest travel, across a vine bridge and into the midst of a batch of primal banelings.  Clear them out and then send Kerrigan Northeast into a leaping battle with several acid-launching ravasaurs, and the area concealing the last Xel'naga artifact.

Head Northwest through two more ultralisks and a ravasaur, then turn South  and use the Queen of Blades' Leaping Strike to slay several ravasaurs perched on ledges to the South of the path while your main force clears out closer-range units on the path curving to the West.  Be wary of the attacking vines, and make good use of the Mend ability to keep your lone ultralisk in good health and brutalizing anything that dares obstruct Sarah's path.

Several more clusters of banelings await here, interspersed with groups of zerglings and hydralisks and the annoying short-range tentacle plants that seek to impale your units.  What’s more, an ultralisk is hiding on the far West side of the path, in a perfect position to ambush you if you pass it without noticing- don’t let it hide, and be sure to explore the whole path so that you can get the drop on it instead.