After the princess joined me with her elf girl, the president of the warrior union also had a conversation of "I want an elf girl". After the interaction, another El was added. Now I have two Els. The above content is machine translation. If there are any errors, please excuse us.

The same thing happened to me after I spoke to Duncan in Chapter 1 — I got a second Aire, too.

I chose the slave route with the princess. First, I obtained her heirloom bracelet, and then I convinced Aire to help me find Anastasia.

Aire(s) also seem(s) to be counted as a regular character (white name), rather than a unique one (yellow name). I can sacrifice her for stats, and so on.

Resurrection spells also stopped working.

0.11.0b save

For some reason, in 11.0b Aire's unique tag was commented out. I uncommented it and Aire  works as usual.