In order to create an Elf troop tree simply add the tag "race="elf".

Example
   <NPCCharacter
id="elf_example"
               name="Elf"
default_group="Infantry"
occupation="Soldier"
culture="Culture.empire"
race="elf"
       is_basic_troop="true"
level="16">
       <face>
       <face_key_template value="BodyProperty.fighter_empire" />
   </face>
   <skills>
   <skill id="OneHanded" value="42" />
   <skill id="Polearm" value="42" />
   <skill id="Crossbow" value="39" />
   <skill id="Athletics" value="38" />
   <skill id="Riding" value="21" />
   </skills>
   <Equipments>
       <EquipmentRoster>
   <equipment slot="Item0" id="Item." />
   <equipment slot="Head" id="Item." /> 
<equipment slot="Cape" id="Item." />
<equipment slot="Body" id="Item." />
<equipment slot="Leg" id="Item." />
<equipment slot="Gloves" id="Item." />
   </EquipmentRoster>
   </Equipments>
   </NPCCharacter>
Enjoy

The project has now been left behind.

15/7/23
@everyone As of today I am officially retiring from the Mount & Blade 2: Bannerlord modding community.It's been a blast but life has shifted my main focus away from modding where it's returned to normal. Sadly this does mean that project I was working on will no longer be supported or otherwise engaged with. Over the last few years I've watched as teams and their mods have come and gone and in some cases seen themself rip apart over seeming petty things.First things first, thanks are in order, I'd like to thank people who have stuck by me from the beginning back when my only work was Kingdoms of Aeraleon or Alantos as it was known back then. So thank you <@731666578533515285> <@449016352175423509> and sadly not in this server but also <@133253987439738880> . I also want to thank a few of the people who glanced through my mods and taught me a thing or two like <@186583927417208843> and Dawa. I'd also like to give special mention to Badger for providing me with some amazing pieces of artwork.Second, I will leave my discord account open for at least one more month so any modders in the server can ask for any pieces they would like to have for their own projects (finished or not). Please don't hesitate to ask for anything as I can provide it.Third, To any modders who read this, good times or bad don't try to come together at every chance. People will let you down of course they will but don't push them away for it. When life gives you potatoes you make potato alcohol (just kidding, of course you make chips). Always try to work together so you can make something magical.Lastly. I guess it's goodbye, we had some fun didn't we. If we ever meet again I hope your doing well.I will still be writing the story of this world so keep your eyes peeled one day you might see something!I was naughty. Nearly forgot you <@255844535618240514> Thanks for your help tooT.D.W_Hayster