Aserai Recruit
The guide describes the Aserai Recruit path as leading to good Mameluke cavalry units. Its example identifies a Desert Horse as required for upgrading an Aserai Mameluke Soldier into an Aserai Mameluke regular cavalry unit.
How it works
The source says cavalry upgrades require an extra horse matching the troop type, and in this example the Desert Horse can be bought in Aserai cities or looted from a defeated Aserai army. The guide also says troop upgrades usually cost gold and raise daily wages.
When it helps
Consider this path if you want the described Mameluke cavalry progression and can provide its required horse.
The tradeoff
The cited example's cavalry upgrade requires a Desert Horse.
Your next step
Check the horse requirement before attempting the described cavalry upgrade.
Read the supporting references
Check the edition and source version for patch-specific details. Guide methodology.