I am not really sure why Oda is just sending Gaban in like that, he should whoop the floor with them. The Holy Knights seems not like a big threat considering the man power we got on Elbaph - Gunko getting the best of the Colon SH‘s isn’t really an indicator, because they simply got caught off guard by her DF ability. Not the first time happening.
So why sending Gaban in?
Now the possibility that most people mentioned, is that the HK are gonna use Colon to trick/black mail him or whatever - also Sommers thorn DF seems to get stronger the more love the parent has for their child, but at the same time, i don’t see a DF getting the best of Gaban. He is just too OP and experienced for that to happen.
But you never know with Oda.