He was well on his way to get his castle until he got emotional. Band of Hawk contracts didn't say he was gonna give them nikkas up to man eating demons.
I disagree but if we're doing that than the whole band were heels. Griffith at one point questions himself to Guts, and breh gives him the cosign Whatever Griffith said to the Princess Charlotte Guts was his homie and what he does to him after is a betrayal.
To me Griffith was always a heel, the band were just his tools swayed by his charisma. Griffith loved guts but with as with all things it was tainted as everything had to be under Griffiths terms, if he was a real homie, he would have let that man walk away.
Did the band ever know what they were fighting for?