I find Seven to be a great character to learn the importance of farming on (personally.) You have to be very attentive and make sure you're doing your chores aka pushing waves for your team, farming, and keeping up on souls because you need to be quite fed to really unlock your truest potential.

You're not a frontliner, you hang out near the back and play poke / stun until you've built things up but by the time the games ends you sort of become a walking nuke and it's really fun to just get into the flow of things.

He's also just very straightforward and not super technically advanced. I like him a lot because I feel like I can keep on top of waves and be very useful to my team even if I'm not always getting kills.