Surprisingly, a skill that hasn't been that useful for the twins for a long time came into hand on this occasion.
'Death Style, Fifth Form, Mirage Assault!'
Another three Reans and Roans appeared around them, creating perfect copies of the twins. After entering the Void Tempering Realm, this skill became pretty useless since the copies themselves couldn't get any stronger. Above all, due to the Natural Spatial Perception, they couldn't be used to fool the enemy either.
Taking someone like Eagon, for example, just his normal Divine Energy Barrier would be more than enough to completely stop any attack of all clones at the same time. Simply put, he could simply pretend they didn't even exist. That's why the twins hadn't used the Mirage Assault anymore.
Right after, they used their skills.
'Death Style, Second Form, Crescent Moon!'