Link Summon System
A Link Summon system is an ability in Kingdom Hearts 3 wherein Sora calls characters from other worlds to aid him in battle.
The Power of Links
The system revamps the skills of various characters, adding more flare to their attacks. In the image above, we can see Simba infused with Fire, which allows him to burn enemies to the ground. The image below then shows Ariel imbued with the element of Water.