WARNING: The following contains spoilers for The Irregular at Magic High School Season 2, Episode 4, "Visitor Arc IV," streaming now on Funimation.
The Irregular at Magic High School continues its all-action pace as Tatsuya overpowers Angie Sirius's trademark spell Parade to reveal her true identity: the American transfer student Angelina Kudou Shields. However, Tatsuya is on the ropes when Lina's fellow USNA agents leave him outnumbered -- until a surprise intervention turns the tables completely. It's this shift that allows Tatsuya to acquire some critical new intel on the Vampires and the possible origins of the supernatural parasites.
Rather than all-out enemies, Tatsuya and Lina's relationship is developing more into a frenemy-like rivalry. There's no hatred or intent to kill from either one, only a strong desire to accomplish their conflicting goals while keeping their most important secrets. Lina is currently struggling on both counts, however. As Tatsuya shares newly acquired information with a few of his classmates, over in the US Shizuku learns some shocking news about where the parasites may have come from.
After Lina is unmasked, her battle with Tatsuya intensifies. She manages to hurt him, so Tatsuya throws a grenade-like object into the air, which explodes with blinding light. Not wanting to reveal his superhuman abilities, Tatsuya heals himself while Lina's blinded and manages to pin her on the ground. Lina calls for help and her USNA team of "Stars" agents appear, severely outnumbering Tatsuya. But, just as Lina somberly prepares to finish him off, Miyuki shows up and freezes every one of the Stars with one enormous magic attack. It's a timely and refreshing return to form for the sister Shiba, who has been mostly sidelined through Season 2 until now.
Tatsuya then requests an uninterrupted one-on-one battle against Lina. The stakes: if Lina wins, she gets to go free, if Tatsuya wins, she has to answer all of his questions. As Lina has little choice in the matter -- and is desperate to prove her abilities as a Strategic-Class magician -- she agrees. However Miyuki, still furious at seeing her beloved brother's life in serious danger, demands to fight Lina on his behalf. An absolutely titanic magical battle ensues, though Tatsuya ends it prematurely by stopping an attack from Miyuki that's so powerful it would have killed Lina had it hit her full-on. Lina acknowledges her defeat and gives Tatsuya some valuable information, which he later shares with his comrades hunting the Vampires.
Although the Vampires aren't directly involved in the action this time, they continue to be investigated on two different continents. Shizuku, still studying abroad in the United States, has a well-connected American friend who delivers some stunning news: the parasites controlling the Vampires first appeared after a scientific experiment to generate and eliminate black holes went haywire. It's unclear who performed the experiment or for what reason, but this information also connects with the revelations Tatsuya gains from Lina.
The parasites can infiltrate the bodies of people and change their very nature, bringing out any dark desires in their hearts. This influence -- which formally turns them into Vampires -- likely also caused the USNA military magicians to desert and go to Japan. Tatsuya shares this speculation with Mayumi, Katsuto, Erika and Mikihiko, all of whom are investigating the matter with their own motivations. But why are the Vampires committing murders? What purpose do the parasites serve by changing a human's nature? We may have the answers soon -- just before battling Lina, Tatsuya fired a transmitter into one of the Vampires, meaning his group now has a way to track the parasite's movements.
But perhaps the most intriguing part of their conversation is what didn't come out: Lina's identity. Lina hasn't yet discovered Tatsuya's secrets -- most notably that he is the magician behind the "Scorched Halloween" incident -- so Tatsuya could have shared the true identity of Angie Sirius. That he chose not to, as Miyuki later happily points out, is a sign that he does feel some form of affection for people besides his sister.
The feeling is mutual but Lina, who does not possess a cold-blooded killer's instinct despite also being a military magician, continues to struggle both personally and professionally. She likes Tatsuya and Miyuki but her pride and reputation have both taken a severe dent, while she remains no closer to discovering the answers behind the USNA military deserters or the parasites. On the flip side, she didn't battle either of them with the intent to kill and still maintains her goofier side even intense moments. But the fact remains that Tatsuya is the magician she and the USNA are searching for, while he and the others investigating the mysterious murders now possess crucial information that will help them move forward with confronting the parasites. For now, at least, the intriguing frenemy relationship they share seems set to continue.