However, it was almost impossible to do that. If Zhao Hai didn't have his dimensional space, he wouldn't be able to deal with 100000 dujie-stage undead creatures at the same time even if he had 1000 immortal-stage undead creatures.
However, Zhao Hai had the space, which allowed him to deploy his forces to any location on the map. That was why he used one billion creatures to surround 100000 dujie-stage undead creatures and bring them into his space. Before the immortal-stage undead creatures could react, Zhao Hai had already finished his job.
Once Zhao Hai finished off the 100000 dujie-stage undead creatures, he immediately led his Army to surround the immortal-stage undead creatures.