Sterfen's Opportunity to Strike
Sterfen was a first-hand witness to Halmut's mental decline. He personally saw Halmut torch his entire conference room in paranoia, albeit Halmut nearly caught Sterfen off guard with such an act. The Assassin God was astounded to see the great Sun God constantly on edge and doing every little thing to guarantee his safety. Halmut's cautiousness went far beyond extreme when there were supposedly no eyes to witness his acts, not to mention the unusual and sporadic conversations Halmut had with himself while alone.
Patient as ever, Sterfen was sure that such a decline would eventually prove useful for him and offer an opportunity. Now, Sterfen's patience had paid off.
But Sterfen wasn't going to take Halmut's sudden change of attitude lightly. As the best assassin would, Sterfen made sure that all his ducks were in a row before stabbing them all through the throat with a single strike. That's how he worked and how he was trained.