Dead, seriously injured in comic 83. In comic 84, in order to prevent him from continuing to suffer, the commander gave the giant needle to Almin, and then Alvin died in battle.

In Chapter 83 of the comic "Decision of Life and Death", the only survivor of the attack by the ape giant - recruit Flock - returned to the Shiganshina District, but was seriously injured and was in critical condition.

The last sentence of the comic chapter 84 "White Night" is a question he asked the teacher in class when he was unconscious, and it also implies the ideal that has always supported him in his struggle. Levi finally couldn't bear that Alvin had to live in mental and physical hell, so he decided to free him and gave the titan injection to Armin, so Alvin died in battle. Extended information

The experience of Alvin Smith, the thirteenth generation leader of the Survey Corps:

During the 57th investigation outside the wall, the giantess capture operation was carried out. You have to make many sacrifices and end up in failure, and you must be held responsible for this. However, the entity was later successfully captured. For the sake of the survival of all mankind within the city wall, he can choose to give up the lives of 100 companions. He is a person who can give up the most important thing.

Although he seems cold and ruthless, it is precisely because of this that he can be deeply trusted by his subordinates headed by Levi. Always put the overall situation first, even if it means sacrificing subordinates for victory. When he led Allen and others to investigate outside the wall for the first time, he used Allen as bait to attract the female giant and captured her alive at the expense of a few lives.

Unfortunately, I didn’t expect that the female giant could summon other giants to eat her, causing the capture operation to fail. Later, when the Survey Corps was at the end of its rope, Armin's strategy was used to expose the true identity of the female giant and successfully capture her alive, reversing the situation in one fell swoop.