hi Alam,
Yes right that the figur looks like a human who wearing a wayang headgear

. Hei.. thats not just imagination.. Different with me who always imagine when I have the superb collections of Keris Sumatera, Bugis and Semenanjung like yours..
Also thank to Newsteel, you have same opinion with me that the figure is a king wearing the crown in squatting position
By more pictures we can know more about the keris styles.. and I hope other forumities will post another keris with relief too for reference