Arkhen spent one whole day in the Undead Realm and refilled his Undead Army with strong tier-2 undead monsters. Of course, he couldn't make his army full in just one day.
Tier-2 monsters also had grades, and they corresponded to the 1st realm's power stages.
For example, a Tier-2 / 3rd-grade monster was as strong as a 3rd-grade beast or 3rd-class powerhouse stats-wise.
Arknen roughly got 17k undead monsters in his army after a day of farming.
3894 Undead Ghouls (Tier-2 / 4th grade)
6538 Skeleton Knights (Tier-2 / 4th grade)
6594 Undead Liches (Tier-2 / 4th grade)
Arkhen only had 4th-grade monsters in the army because he only started killing after flying deeper until he encountered 4th-grade undead monsters.
After all, there was no point in wasting time to kill 2nd or 3rd-grade undead monsters. It was better to use that time to kill more 4th-grade undead monsters.
