Complex sentence: During the issue, Nekron nearly reenters the living universe when the supernatural activity mysteriously increased throughout and over this given the opportunity to briefly controls of every deceased member of the Green Lantern Corps.
Split into simpler sentences: During the issue, Nekron nearly reenters the living universe when the level of supernatural activity mysteriously increased. This increase gave Nekron the opportunity to briefly control every deceased member of the Green Lantern Corps.