yooooo okay so im a reputation 18
for a beginner Warden may be best
Raider is a good choice as well
If a character is labeled Hard, give them a bit and then learn them in Hero Tactics
I advise that you stay away from Conqueror, Lawbringer, BERSERKER (for sure), Jormangundr, Highlander, Valkyrie, Shinobi, Orochi, Nobushi, Jiang Jun, Shaolin, and Zhanhu
It's a mouthful, but vanguards will absolutely sic up opponents in early leagues, and once you get hard feints down you should be set to learn those characters above