You can walk with Yae miko and Raiden Ei but Raiden is very small like a kid but she is still Raiden Ei but just a little more naive. Yae miko is annoyed with Raiden because she is now small and is kinda annoying to deal with so she hands Raiden off to you to take care of you. Since Raiden is small her vocal cords are now smaller which means it harder for her to speak and it is hard for her to pronounce words like please, help, etc because she can't pronounce an l sound so it sounds a w sound