Complex sentence: Atrocitus is able to uplift his fellow Red Lanterns to their previous mental acuity with his shamanistic magic: the ritual, employed only once on Bleez, restored her previous mindset and ability for coherent thought, without dimming her rage.
Split into simpler sentences: Atrocitus is able to restore his fellow Red Lanterns to their previous mental acuity with his shamanistic magic. The ritual, employed only once on Bleez, restored her previous mindset and ability for coherent thought, without dimming her rage.