Bloodlust

The Bloodlust ability is a Special Buff shared by both the Hellhound Vehicle, and the Hero Infantry unit, Kara.

Both of these buffs have slightly different effects despite sharing the same name.

For Kara, as stated by WrongThinker on the KIXEYE Forums in the thread titled, Hidden Unit Stats: Revealed, this Buff increases her damage output for each unit she kills in battle. The buff caps her damage increase at 200% more than her original damage. It also reduces her reload speed by up to 50% at maximum.

“	Any time Kara or a Member of her SF Team kills any enemy unit, she gains a 10% bonus to Damage and a 5% increase to Reload Speed, up to a maximum of 200% bonus Damage (after 20 kills) and 50% increased Reload Speed (at 10 kills, thus reducing her reload time to 1 second when maxed).	”
	— WrongThinker, Hidden Unit Stats: Revealed

For the Hellhound, the Bloodlust ability only decreases the unit reload speed up to an unspecified amount.