From the Malifaux Tactica Wiki:
Nekima is a dual role minion with specialized abilities to provide support, and hard hitting melee power. She does however lack, in the resilience department, and costs quite a lot of SS to bring on the table.
Since this model’s release, there was an important change to the Nephilim Heart ability, restricting its application to Terror Tots and Young Nephilims only. This prevented some abuse from the synergy Nekima had with other models, but also severely limited her support abilities to specific minions.
With the latest FAQ update, Wyrd stated that “Nekima will get her turn” so we can expect that somewhere down the future, she will get a touch up, but there is no way to know to what extent this will affect her.
Nekima is quite specific with her synergies. She works well with the typical Nephilim growth list or other Young Nephilim and Terror Tot based lists. However intended, Nekima’s support abilities have short range, and her melee prowess is only really useable if she’s protected from harm.
Nekima plays hand-in-hand with growth lists, because she has means to provide blood counters. Rather than draining blood when she kills, she gets a count whenever a living or undead model dies within 3". This occurs automatically, and even if another model used its Drain Blood, such as a Terror Tot. Remember that most Nephilim are alive and she will get a counter from them too when they die.