The same 神 character is painted over a seal on 2 different artworks:
An early landscape painting (by Wei Xian/卫贤?):
A calligraphy by Wang Xizhi:
Painting over a seal seems rather rare to me. I guess this one is the seal from a collector, but I might be wrong. Do you know a particular reason why it has been painted? And does it have a special meaning (maybe a religious one)?
Edit: here's an attempt to make the seal readable: