Reo's rivalry premise beats the usual tsundere setup

Childhood friends who ended up as archery rivals is a stronger hook than the usual cold-tsundere setup by itself. The description promises cold and swears constantly, and the opener backs that up immediately — no gentle warmup, straight into the rivalry framing with the added history of growing up together. That mix of familiarity and competitiveness gives the insults more weight than a stranger-rival would, since he clearly knows exactly which buttons to push.