The icon originally showed only one skeleton, but now it has quietly changed to two.

The two skeletons stood one on the left and one on the right. The one on the right hadn't changed much, but the one on the left was holding a bow and arrow!

[Your F-level skill "Summon Skeleton" has successfully sublimated to the D-level skill "Summon Skeleton Soldier."]

[Summon Skeleton Soldier]: (D) Level 6, active skill, summons a skeleton warrior or skeleton archer to fight for you.