Strife

MOBAs are popular because of the level playing field on which everyone starts. All characters start in the same place, with a set amount of gold to purchase starting equipment. As the players gain kills, they gain experience to level up their characters, opening up more skills. And then they upgrade their skills, gaining more gold with which to purchase equipment. Strife stands out from other MOBAs by making gold and experience shared among team members who participate in the kill, so squadmates aren't competing against each other. That also means that support characters -- that is, characters with skills that support their teams (healing, shields, crowd control) -- are more fun to play rather than their being the "sacrificial lamb" for the good of the team.

In Strife, the online multiplayer game is further extended by single-player adventures provided for free. These mini role-playing games tell the characters' backstories, and players learn to use all their skills to get them through the adventure. Parents who play the game might be OK with younger kids playing the single-player games, as they're played offline. The largest drawbacks in games like this are the unmoderated language that kids will encounter when they play with strangers, the frustration of trying to coordinate with teammates who have unknown skills, and the long learning curve. Add to this the complexity of endless equipment variations (and, thus, character customization), and you could run into a lot of confusion for novice players. But this depth is one of the game's strongest selling points, so if you stick with trying to understand the nuances of Strife, you'll have a great time either by yourself or with friends.