Complex sentence: Nearly twenty years after the pair had spoken, Ethan decided to pay his old friend Rupert a visit when he sensed that Eyghon had been summoned again and was roaming free upon the world.
Split into simpler sentences: Nearly twenty years after the pair had spoken, Ethan decided to pay his old friend Rupert a visit when he sensed that Eyghon had returned. Somehow, the demon had been summoned again and was roaming free upon the world.