Qiu Tu wasn't teasing Zhao Ji on purpose; rather, he had his own objectives.
During his recent interactions with Larilo, he had discovered a very important issue:
Individuals as significant as Old Master Qin and Jia Wei, such valuable allies, Larilo could readily discard or sell them off.
This indicates that although the Evil God considered believers as tools for gathering power and as a means for descending, He...didn't particularly value them.
This might be because the source of the Evil God's power still originated from within Himself, and the aid from the believers wasn't as substantial as one might assume.
So, if Qiu Tu were to tell Zhao Ji that he was a follower of Larilo, in the eyes of someone like Zhao Ji, a Great Evil God, it would be equivalent to Qiu Tu introducing himself as: I am a disposable, one-time... item of Larilo.
Therefore, after Qiu Tu devised his plan to deceive Zhao Ji, he began to ponder which identity he should use.