When I activated a ritual spell to Ritual Summon Chu Chialain (idk how it spelled) I was wanting to use my Blue Eyes as tribute. However, it was not losted as an option. Is it possible you could add a way so that I can tribute any card I want, as long as it meets requirements?
Did you use Chu Ritual or used Light monster Ritual? With Light Monster Ritual you must tribute the exacly same number of stars
The target of Cú Chulainn's effect needs to be a normal monster in the graveyard.
People generally use Blue-Eyes as the ritual tribute to summon Cú Chulainn, then immediately banish it from the graveyard.
You should explain more details about your situation.
I always Ritual summon CC using blue eyes than banish him to increase CC attack. It works.