Fafnir had once warned Angel that, with his strength, it was best not to directly watch battles of a high level. If he really wanted to, he had to use an indirect medium, like the strand of wind Fafnir had used previously as an indirect tie to view the battle.
The reason Fafnir had advised so persistently was that, firstly, with Angel's power, rashly watching high-level battles wouldn't teach him anything; secondly, it might affect his future choices and could also cause lingering damage to his own energy operation.
Angel hadn't taken it seriously at first because when he was above the Void Tower, he had also watched part of a high-level battle and didn't feel any discomfort.
But now, as he watched the battle between Aoluxiya and the Lord of the Flameless, not only could he not catch a glimpse of their figures, but he also felt increasingly uncomfortable the more he watched.