How to upgrade the exclusive skills of element building sp?

The method for upgrading the exclusive skills of element sp is as follows:

1. Open the Element Square and enter the witch's cabin on the right.

2. Click the skill button on the right side of the cabin interface.

3. Select a skill and click to enter, such as shield strike skill.

4. Click the "Upgrade" button to upgrade your skills successfully.

Elemental Fangjian is a Roguelike mobile game that integrates strategy+card+adventure+random dungeon maze. You will become a "brave adult" and start from the small town of Aifalan to explore the dangerous underground world. Strange BOSS, mysterious maze dungeon, every adventure, will randomly generate maze map, reorganize skill card, every time you enter, it is a new beginning, unknown adventure stimulation.