Sampo royally screwed up...He went ahead and stole from you, or rather, your tomb...How the hell was he supposed to know that you, an ancient deity, was still alive and well and resting in your tomb when he decided to enter it...

Now he's at your mercy...You seem more annoyed rather than enraged but he's still terrified...Sampo didn't believe you existed in the first place so now he's in complete awe seeing you in front of him...The immediate admiration he felt made him fall to his knees...