Note: Alfonse's route might contain images sensible to some players (e.g. zombies sprites), proceed in his story with caution.
Alfonse is the first son of Walter Goldstein, and is consequently the older brother to both Klaus Goldstein and Elias Goldstein. He is an official researcher of the Ministry of Magic, and has gone on journeys with them.
When they were young, Alfonse was described by Elias to be gentle and always nice to him. He and Klaus argued often, but all the same trusted and supported each other a lot, filling in where the other failed.
It was also remarked that it was because they trusted each other so much that Klaus held a great amount of anger at Alfonse when he left, going as far as to make Elias wary of mentioning Alfonse's name around Klaus, and making Klaus say that Alfonse wasn't their brother anymore.
He also had a previous engagement with Elaine, who was his childhood friend. While they were close enough to be best friends with each other, Alfonse admitted that their engagement was arranged by their parents.
Three months before their wedding, Alfonse decided to head out on a brief journey to find Vita dragons, to further his research. He was interested in their longevity and regenerative abilities, and said that because Vita dragons only stay a month in their chosen habitat before leaving, that he had to chase a lead on their location urgently. Elaine proceeded to ask him if their wedding or his research was more important, to which he hesitated and answered that both were as important as each other. Upon hearing his answer, Elaine said that his research was more important to him, since he hesitated before answering and cancelled their engagement. She then told him that she was going to follow her own wishes like him.
His abrupt decision to leave the Goldstein house and put his studies on hold without explaining his reasons to anyone resulted in the Goldsteins being angry with him, with Klaus the most noticeably angry of all.
During his journeys, he joined the Ministry of Magic as a researcher.
He eventually returned to the academy to further his research, and became a prefect again.
Alfonse was first mentioned in Klaus' main route, though not by name. Elias told MC that he was their third brother and the fiance of Elaine, and this was confirmed by Klaus. He appeared for the first time in Klaus Goldstein main route I sequel. Alfonse only revealed his name and it was unknown if he was a student or a visitor. Liz Hart often thought that he reminded her of someone, but she could not figure out who. Elias Goldstein has had a glimpse of him, but he dismissed this idea, mentioning that it was impossible for Alfonse to be in the Academy by then. Alfonse was also shown in Elias' event story of the Night Class. Elias was shown to be surprised to see him, but he never disclosed to Liz who Alfonse was, since he was a disappointment for the Goldstein family. In Season 6 it was revealed that Alfonse is a prefect for the Day Class. Quite knowledgeable on magic potions, he previously joined the ministry’s research trip, and he had just recently returned to Gedonelune.
In Alfonse's route, he served as a Day Prefect, working alongside Caesar Baroque and Liz Hart. He also worked as a researcher of the Ministry of Magic. While researching, he also set up a clinic for the poorer residents of Gedonelune and was seen as a capable doctor and a hero by the residents.
At the beggining of the route Headmaster Rembrandt had asked the prefects and deputy prefects to go over to a part of the Academy that's closed to students and asked to investigate something that appeared to be odd, although he doesn't define what it was.When Zeus, Hiro, Caesar and Liz along with Yukia and Elias are looking around, infected people appear before them. After fighting them and seeing they couldn't get hurt, Zeus and Hiro grab Liz and run away. After they stop for a moment other infected people are there and when Liz is about to be attacked Alfonse appears and uses a magic spell and potion to return those people back to normal. They're all happy to see him and Alfonse explains that he just got back from a trip he had made. He declares that the people are infected with the Black Rope Disease which is still uncurable. He tell Zeus, Hiro and Liz that they need to take those people to the infirmary where they can be treated and after that he disappears which annoys Zeus and goes after him. Seconds later Caesar, Elias and Yukiya show up too and help Liz to take the infected people to the infirmary.
The next day, Liz sees Alfonse from the distance and is wondering about how secretive he is. Headmater Rembrandt explains -after scaring her for showing out of the blue- that Alfonse is a special case but he can't disclose more information. They're interrupted by Luca and Rembrandt leaves. Luca shows Liz an article from the Gendolune Times that said that Klaus had girlfriend. Alfonse who had overheard tell them it's a lie and that they shouldn't believe everything that the reporters say for they tend to twist things in order to sell more papers. Later, Alfonse walks Liz back to her dormitory, but he spots Klaus and asks Liz to hide. Klaus walks nearby where Liz and Alfonse had been standing but believing he had imagined things and goes back to the dormitory entrance to wait for Liz. Alfonse lets her go and walks away unseen by Klaus, which makes Liz to ask herself why Alfonse was avoiding Klaus and recalling how tense their relationship seemed to be. Then she approaches Klaus, who had come to see her to ask for a favor: Due to the article from the Gendolune Times, Klaus needed Liz to pretend to be his girlfriend at a party held by the Goldstein family in order to get rid of future girls who would be over him trying to force him into a relationship. Knowing that Klaus is not the kind of person to ask for anything and understanding Klaus position, Liz agrees to pretend to be his girlfriend.
The next day, Liz arrives too early to the meeting Klaus had set up. While walking around town to kill time, Liz finds out about a part of Gendolune that's not often known or seen by the other habitants and discovers that Alfonse had set up a clinic there to treat people. She asks Alfonse if she can help him which he accepts. Later, she meets Klaus, who had made arrengement so she can be dressed up for the party.
Alfonse is shown as a calm, easygoing, polite and caring person towards his friends, normally getting along with everyone except Klaus. As mentioned in-game, Alfonse is somewhat carefree when it comes to certain obligations since Klaus had to told him off every time there was a task with a lot of responsibility. It's shown that he gets down when Klaus gets angry at him.
He loves his brothers a lot, and as such blamed himself so much for their pain when he left, that he believed himself to be undeserving of love.
Despite being calm and polite it's insinuated that Alfonse could be quite dangerous as an enemy. This is shown in Hiro's route when during a reunion he falls asleep after getting drunk. Zeus, Caesar and Klaus draw his face with doodles, and after he wakes up he tells them how mean they were. He then threatens them with a revenge of his own but he does it with an evil grin which scares Caesar and Zeus.
He dislikes the press and the media greatly, as they "invade people's privacy, pretending to do so for justice" and that they "love twisting the truth only to grab people's attention". This is one of the reasons why he left the Goldstein house for his research, as they had to deal with politics and the press while continuing their research.
He also admitted near the end of his route that he saw his past self as having been overly optimistic and naive, and that if he had been more communicative with his brothers, then maybe they would've understood his reasons for leaving.
In Klaus main route II, it was revealed that Alfonse has a low intolerance of alcohol, such that even soft drinks with low alcohol content was enough to get him drunk. When drunk, Alfonse acted by instinct, showing his passion of some rare and dangerous plants to his friends, however, with no sense nor tact of danger, this placed them in funny yet awkward situations.
It was also mentioned that Alfonse and Klaus pulled a prank on Elias when he was really young, making Elias scared of Halloween.
Alfonse's specialization is in magic potions and Plants.
Alfonse carries a book which is a log, of all the plants and potions he has encountered during his journeys. This book has the ability to reproduce the plants he has recorded, allowed the experiences to be relived.
The subjects summoned from Alfonse's book can return to it by using the dispelling "Supesaman Mundi". Immediately, the subject glows brightly, then slowly fades until it vanish.