It's "Lord of the Rings"
"It's a perfect match for this kind of game," Olander replied when I asked him why they chose to use Lord of the Rings. "It was a no-brainer for us."
The MOBA genre can be rather off-putting to noobs, and "this gives you an automatic sort of interest and entry point," Olander explained. "It's like, 'Oh,' you know, 'I know Middle-earth. I know who Gandalf is. That's cool.'
"The other thing that it does for us is it's very interesting with the Guardian creation itself," he continued It gave us a chance to sort of say to ourselves, 'What would I think that Gandalf would play like? What kind of powers do I think he would have?' You know, which is very interesting. So it becomes a very sort of intuitive experience for players."