Lionet Ban is a B-rank unit with an AoE retaliation-style damage mechanic. In real gameplay he is mostly a collection character, as B-rank units are quickly surpassed by other options in both consistency and overall combat value.
At max skill levels, his kit revolves around Lionet Bombard for teamwide chip damage, while Pounce adds occasional single-target taunt pressure. Lion Roar can stack bonus damage for Bombard when Ban takes large hits, but this requires him to survive heavy damage repeatedly, which is unreliable given his low durability. Even with stacks, his output and control impact remain too modest to compete with stronger low-cost controllers.
Overall, Lionet Ban can be used briefly in early progression if your roster is very limited, but he has little long-term utility. For efficient account growth, replacing him with an A-rank or S-rank control or AoE pressure unit is the better path.