Piss mark
Fenik had been quite cooperative over the day. One would guess that he was trying to make up for past mistakes, but Bardeelus didn't see any regret behind his brother's eyes.
Fenik was sad, depressed and more contemplative nowadays, but he didn't seem regretful. Aside from that, the only reason he agreed to lend a helping hand on these recent plans, was because he had become fearless over the weeks!
He wasn't scared of the monsters, and certainly understood them at a deeper level. For that matter, he was willing to indulge in this plan wholly, in the hopes of uncovering any secret that had gone beyond his head before. He felt ready to handle anything!
As for Bardeelus, he didn't expect anything more than that out of his brother. It even was surprising that Fenik agreed to the plan, as Bardeelus had expected ridiculous excuses instead. Cooperation of any kind, seemed godsent.