The look in Sae Itoshi's eyes when he notices Bunny Iglesias in Blue Lock chapter 307 speaks volumes. That one cold face tells fans so much—hatred, rivalry, maybe even unhealed pain. Some fans theorize that Bunny's appearance might have stirred up long-lingering frustrations connected to Sae's objectives, or perhaps something stronger and deeper is going on between them beyond their rivalry.
Was Sae challenged, threatened, or, even worse, haunted by a rival who resembles someone who once broke his dreams? Although we don't have all the answers just yet, that one intense panel holds the anticipation of what is to come, one involving the clash of pride and purpose.
Disclaimer: The article reflects the opinion of the writer, and it includes spoilers from the Blue Lock chapter 307.
Exploring the reason behind Sae Itoshi's anger after seeing Bunny Iglesias in Blue Lock chapter 307?
Sae Itoshi’s cold glare at Bunny Iglesias in Blue Lock chapter 307 wasn’t just a panel—it was a statement. While the story doesn’t confirm why Sae looked so visibly irritated, there are multiple threads hinting at an underlying emotional conflict.
For starters, Bunny Iglesias may not be the direct reason behind Sae abandoning his dream, but he likely represents a painful reminder of someone who was: Leonardo Luna. Iglesias and Luna appear to have a visual likeness, but there also appears to be an aura of emotional hurt and interior isolation, which would account for Sae's bitter response.
Sae's anger probably isn't aimed at Iglesias in particular. Perhaps Iglesias brought back memories of Luna, the striker who had the very same position Sae sought to fill at Re Al. If Sae noticed Iglesias, someone who appears or plays like Luna, having success at rival club Barcha, it might have triggered resentment based on Sae's failures in the past.
Sae's collapse wasn't due to a lack of ability, but rather a combination of intense club cultures, insidious racism, alienation in Spain during his youth, and overwhelming competition he couldn't overcome. Facing another iteration of that trauma reopens the wounds he's kept hidden.
Additionally, Sae and Iglesias may have been rivals at one point, engaged in competitive exchanges. If Sae lost critical moments to Iglesias while in Spain, it would further explain his frustration, especially if those losses were the final nails in his dream's coffin.

The moniker "Cocky Chicken" might even be something Sae was once called by Iglesias, suggesting that Iglesias had perhaps unintentionally taunted Sae for her shaky self-assurance at the time. Combine that with the potential for Iglesias to be related to Luna, either bloodwise or by theme, and Sae's glare becomes understandable. It wasn't about the present competition. It was about all of the things Sae couldn't run from.
Curiously enough, Sae didn't seem defeated—he seemed energized. This might suggest Iglesias is less a source of trauma and more of a stepping stone. Defeating him might reignite Sae's competitive nature and cause him to confront his past directly. If that's the case, Bunny Iglesias is not Sae's enemy—but rather the test Sae must pass before he can finally deal with Luna.
Final thoughts

Sae Itoshi's glare at Bunny Iglesias in Blue Lock chapter 307 suggests that Sae has pain from something other than rivalry. While Iglesias likely didn't shatter Sae's dreams, he probably is quite similar to Leonardo Luna, the striker who did.
Iglesias’s appearance and the emotional feelings he triggers for Sae likely reveal his lingering resentment based on Sae’s earlier failures, potential racism, and feeling isolated in Spain. Now, rather than destroying Sae, Iglesias can be the central player who reignites his competitive flame.
Related links:
Blue Lock: The Blue Lock project, explained
Who wins in U-20 Japan vs. Blue Lock? Explained