Try replacing cultures by colors

[verdie-g]

No description provided.

[verdie-g]

<?xml version="1.0" encoding="utf-8"?>
<BasicCultures>
  <Culture id="red"
           name="{=empirefaction}Red"
           is_main_culture="true"
           default_face_key="000fa92e90004202aced5d976886573d5d679585a376fdd605877a7764b8987c00000000000007520000037f0000000f00000037049140010000000000000000"
           color="FF4E3A55"
           color2="FFDE9953"
           cloth_alternative_color1="FFDE9953"
           cloth_alternative_color2="FF4E3A55"
           banner_background_color1="FF7739a7"
           banner_foreground_color1="FFf1c232"
           banner_background_color2="FFf1c232"
           banner_foreground_color2="FF7739a7"
           faction_banner_key="11.4.124.4345.4345.764.764.1.0.0.163.0.5.512.512.764.764.1.0.0" />

  <Culture id="blue"
           name="{=aseraifaction}Blue"
           is_main_culture="true"
           default_face_key="000fa92e90004202aced5d976886573d5d679585a376fdd605877a7764b8987c00000000000007520000037f0000000f00000037049140010000000000000000"
           color="FF965228"
           color2="FF4F2212"
           cloth_alternative_color1="FF4F2212"
           cloth_alternative_color2="FF965228"
           banner_background_color1="FFA97435"
           banner_foreground_color1="FF41281B"
           banner_background_color2="FF41281B"
           banner_foreground_color2="FFA97435"
           faction_banner_key="11.45.122.4345.4345.764.764.1.0.0.463.0.1.512.512.764.764.1.0.0" />
</BasicCultures>

works fine if you do the workaround from https://forums.taleworlds.com/index.php?threads/custom-class-division-and-culture-crashes-in-missionmultiplayergamemodebase-onmissiontick.459553

Also a banner image should be added to the assets. It's used for example in the team selection.