Fuku Bei/Bei Fuku, either pairing is fine, with them switching roles. This is not an all-Bei story!
A continuation of Fukuide K's ending, based on the author's Ultraman: Sai Bei.
Just my personal take, so don't connect it to the original work. Third person/first person.
"Lord Belial, K has always wanted to earn your attention."
"But... you always keep your eyes on things that don't matter."
Lord Belial, why did you make me forget you?
K will always want to follow Lord Belial.
I... I overstepped my bounds, but I have never regretted it.
Lord Belial, you've saved me once again...
I highly recommend