Yogiri immediately understood what these creatures were. They were the Seyla from the floating continent. They were immortal plants, latching on to other creatures to fuse with and infect them, falling from the sky. Yogiri killed the few bundles of them on the rooftop.

-Volume 12 page 51

“They seem quite different than what we saw before. On Belm, the Seyla was not nearly this active and had not transformed its victims to this degree.”

The creature that came through the window was humanoid in shape, but the ends of its arms and legs came to sharp, bladelike points instead of hands and feet.

“Make sure you do not touch it.”

“Die,” Yogiri’s voice came from behind them. As usual, the creature that had come through the window collapsed motionless to the ground.

...

Stepping out into the hallway, they headed to the stairs and started climbing to the roof. They came across some of the Seyla on the way, but Yogiri had no trouble dispatching them.

-Volume 12 pages 92 and 94