There was another drawback to this spell.
A wizard needed three steps to cast a spell: extracting enough mana from mana pool, using the mana to construct a spell model, and unleashing the spell.
The first two steps were performed inside mindspace, while the last step required someone to make the spell happen by using their body as a medium so that the spell could enter the reality.
However, using someone's soul to channel a spell equaled temporarily making their soul into a magic conductor, which would be prone to hazardous energy in the environment.
Even with these problems, Soul Manipulators still regarded Soul Link as an important spell because it had an extra, irreplaceable merit that allowed wizards to transfer the essence of their presence into their souls before their bodies were killed.