[quote=@Lucius Cypher]
I think Gecko means that Greg will intentionally fuck up the mission by blowing Artoria's cover.
[/quote]
Not quite, idea from what I understand is that Artoria appropriately senses danger upon opening the default Hell portal to Celestia, tries to nope, finds Greg waiting to use it.  He then punts her through it and goes through himself to build up a little strength before a proper fight breaks out.

[quote=@Lmpkio]
Ghelgath may go with Henry... and may be the one that retrieves Fran idk.

Mephilus will just be Mephilus. Might just wreck some face.
[/quote]
Greg's already on that, given the opportunity.