The spiritual ruiner for the Bio Engineer is the spirit of the Valkyrie. This is a visually impressive ruiner, summoning a spear wielding warrioress to kill your enemies. Be warned, contrary to what is stated in the official guidebook, it does not siphon a portion of your enemies health back to you. I have used the ruiner countless times against varying foes, at differeing combo levels and I have never seen this happen. People with far more time in the game whose opinion I trust tell me that if you are playing with a Berserker who grants you an extra combo level, and you pop a level 5 ruiner, it will grant you a SMALL portion of health back. So I would say that you have as much chance of that happening as a Champion spontaneously proccing a gravity well from a level 4 ruiner (it can be done). Do not be discouraged by this small flaw however. The Valkyrie is a powerful ruiner who will serve you well.