He has another reason for joining the quest apart from freedom and the sun core. The heroic quest will draw the attention of the gods which will be helpful to Legion-9. Helios knows enough about them to know that they won't miss a good source of entertainment. It is his job to keep it interesting when it needs to be and dull when Legion needs it. Joining the heroic feat was a job before, but the sun core has given him something to look forward to.
Helios prepared quickly. There isn't much to be done to prepare except to burn some of his research data. He doesn't have much that he can take with him either since giants of order don't have anything valuable because of their anti-magic domain. But somehow they always manage to find a reason to fight and kill themselves.
I've started a new book titled DESTINY GAMES. Please check it