Eiko hummed on top of the head of a two-headed Ogre Zombie.
This creature was the latest addition to her Terrorist Squad, and she named him BataBoom.
After seeing Lux's Skeleton Generator Skill, Hereswith decided to impart her knowledge to him, making the skill evolve into Undead Generator [EX].
Because of this, Lux, Eiko, and Asmodeus, were now able to generate any Undead-Type Monster, and were no longer limited to Skeletons.
Shax was a special case because there had been a mutation when Lux had created him using the Skeleton Generator skill. This also led to him being unable to control the Nightgaunt at the beginning because its Rank had surpassed the Half-Elf's rank.
As Lux's Beast Companion, Eiko also learned the skill, Death God's Aura.
But, the Baby Slime wanted her Slime party, and the Terrorist Squad to learn it as well. Fortunately, Hereswith didn't mind and imparted the skill to Eiko's subordinates as well.