Lenny was not a fool. And therefore he did not step against Anguis.
After all, there was a reason that he had not summoned the creature all this time. At the moment, his soul would not be able to handle so much of that pressure. Even with the comprehension of the universe he had been blessed with, he was still lacking when it came to his wounded soul, and lacking of his memories.
Even himself had warned him not to release Anguis.
And now, it had acted. In a way, Lenny was already grateful that the Anguis had not come out of the satan system and into the real world on his own.
Now, that would have been a real disaster. The Holy tool was guided by the energy and magic of its master, but on the condition that its new master did nothing, it could always take that from its surroundings.
Also, Lenny knew that there was definitely still residue of the Morningstar's power within the Holy Tool.