'Lostvayne, I'd be counting on you soon. Go and devour souls.'
Arthur summoned Lostvayne and sent the sword out into the battlefield. The Ego weapon could use cosmic energy to fly on its own and by Arthur's order, it started devouring any souls it could find, regardless of affiliation.
It found a High-Rank Demon on the verge of death and stole their soul, then did the same for an angel, then a dragon, and a god.
With each soul devoured, more of its power was temporarily revealed in preparation for Arthur to use.
'Should I use the Full Release?'
Arthur considered the technique he wanted to use in Plomux when they were attacked by a Half-Deity but decided against it.
There were too many eyes on this battlefield, so unless it was a Deity Level threat, he would keep that card hidden.
He couldn't have people knowing about it and developing countermeasures, after all.