@Jinyo If I remember correctly (and I am to lazy to re-read right now), it went like this:
1. Old man does illegal and forbidden human experiments despite knowing they are illegal.
2. He gets caught and rightfully shunned for his crimes.
3. He makes more illegal experiments in secret.
4. His experiments succed, which results in the golem and MC´s newest harem member.
5. He plans to use the golem to murder everyone who "wronged" him, meaning all the people who are against his inhuman experiments.
6. He also plans to kill the former hero party, which includes MC´s master.
So yeah, he was evil. The only problem is that all of his evil deeds were only mentioned briefly in flashbacks.