Check-In System: I'm a Guard of the Castellan's Castle - Eastern Fantasy

Ye Yu transmigrated to a different world and became the head guard of the castellan's castle. He initially thought that he was going to live the rest of his life in mediocrity, but a Check-In System that was activated suddenly brought him hope of becoming more powerful.
""DING! Congratulations on checking-in at the study. You will receive the reward 'Bright Sun Technique'.""
""DING! Congratulations on checking-in at the forbidden zone. You will receive the reward 'God Level Bloodline'.""
""DING! Congratulations on check-in at the armory. You will receive the reward 'Flaming Godly Sword'.""
...
Fifty years later, a million wolves launched an attack and the castellan's castle was in danger. Ye Yu could no longer stay low profile anymore.