The Pokémon community around them would probably be quite shocked at first. Their friends like Brock might be both surprised and happy for them. However, some of the more traditional Pokémon trainers might frown upon it as they are quite young. But Ash's close friends would most likely support them and help them out, like providing a place for May to rest during her pregnancy.
The Pokémon world's reaction would be mixed. The Pokémon Professors would likely be interested in studying the situation from a scientific point of view, as a human - Pokémon relationship leading to pregnancy is a unique scenario. The local townspeople where Ash and May are known might have a range of reactions from celebration to concern. Some might worry about how Ash will continue his Pokémon - training journey while also being a father, and others might see it as a new chapter in their lives full of potential.
The professors in the Pokémon world, like Professor Oak, would likely be concerned but also offer their wisdom. They could provide resources or knowledge about how to take care of a pregnant woman in the Pokémon world. The other trainers that Ash and Bonnie know might have a mix of reactions. Some might be supportive, while others might spread rumors or be jealous. Overall, the reactions would add a lot of drama and depth to the fanfiction.
Their friends like Brock would probably be very excited. Brock, being knowledgeable about Pokémon and also having a nurturing side, would offer all kinds of advice on taking care of May during the pregnancy. He might even cook special meals for her to ensure she has all the nutrients she needs.
In the fanfic, the reaction in the Pokemon world would be mixed. The local Pokemon townspeople might hold different views. Some would see it as a beautiful thing, a new start for Ash and Serena. Others might worry about how it will impact their Pokemon training. The Pokemon gym leaders could also have different reactions. Some might offer their gyms as a safe place for Serena to stay during her pregnancy, while others might be more hesitant, fearing it could set a precedent that might disrupt the normal flow of the Pokemon training world.
At first, his Pokémon would be startled. They've always known Ash as a human. But then, they would start to adapt. Some Pokémon, like Squirtle, might try to play with Ash in his new form, thinking it's a new kind of game. However, his more loyal Pokémon, like Greninja, would be determined to find a way to turn Ash back. Greninja might use its special bond with Ash to try and communicate with him on a deeper level in this new form, to understand what happened and how to reverse it.
The Pokémon League might condemn Ash's actions. Despite Team Rocket's wrongdoings, killing is not an acceptable solution in the Pokémon world which values friendship and co - existence. Ash could face consequences such as being banned from Pokémon battles or certain areas. On the other hand, some trainers who have been harassed by Team Rocket for a long time might secretly support Ash.
Ash could get angry. He has a strong sense of justice, and he might feel that May has violated their friendship. He could challenge her, not in a violent way, but more in a way to get an explanation and to try to make her see the error of her ways. He would likely be determined to show her that what she did was wrong.
Pikachu would probably be very excited. It might jump around Ash, making little electric sparks of joy. Bulbasaur could bring Serena some fresh berries it finds in the forest as a sign of care. Eevee, if they have one, might curl up next to Serena's belly, as if protecting the unborn baby. Their Pokémon would sense the importance of this new development and do their best to be helpful and protective.
His Pikachu would be heartbroken. Pikachu has been with Ash from the very beginning, and it would likely go into a state of deep depression. It might not eat or interact with others for a long time. Other Pokémon like Charizard would also be extremely sad. Charizard, which has a strong bond with Ash, might fly off on its own, looking for a place to grieve in solitude.
Some of his Pokémon might be very confused and sad. Pokémon like Pikachu, who has been with Ash for a long time, would probably miss the adventures and battles they had together. Pikachu might try to cheer Ash up and convince him to change his mind.
Pikachu would be super excited. It has been with Ash for so long and would see Misty as part of the family. It might play more with Misty's water - type Pokémon. Misty's Starmie could be very protective of the new family unit and use its psychic powers to help around the house sometimes.