Heroes 3.5: In the Wake of Gods Portal > Cloned creatures can be also raised as skeletons with Necromancy skill
Cloned creatures can be also raised as skeletons with Necromancy skill
All killed enemy creatures can be raised as skeletons. This includes sacrificed creatures, cloned creatures, summoned elementals and even war machines. If the victorious hero’s army contains only Skeleton Warriors and there are no empty slots available, the killed enemy creatures are raised as Skeleton Warriors instead of Skeletons.
However, in this case only 66.6% of Skeleton Warriors are raised compared to Skeletons. If there are no available slots and no skeletons (either kind) in the army, none of the killed enemy creatures are raised.