He didn't syphon all of it only half a years worth but that was enough to cause the ritual to fail since the ring needs a years worth to work.
As for the second method, Lumian sensed a strong feeling of inevitability and an undeniable sense of coincidence.
Fantasy · Cuttlefish That Loves Diving
What if he's the child that escaped from cordo?
"I'll follow you until I can earn my own living. N-now, I'm still a child!"
Fantasy · Cuttlefish That Loves Diving
It's not a matter of the ability being useless it's a matter of circumstance. It's just like saying Lumians fire ability is useless cause he's fighting an enemy under water and can't put the full effect of his ability to use.
As the gaseous anesthetic created by the dark-green vines and dark-red flowers permeated the room, Loki's initial impulse was to craft an air straw nearly 30 meters long and extend it high into the air to breathe fresh air. However, he quickly dismissed the idea.
Lord of Mysteries 2: Circle of Inevitability
Fantasy · Cuttlefish That Loves Diving