Disclaimer this is mainly speculation but this will include a spoiler of what happens to a certain character at the bottom.
Now as we all should know by now shipmaster was a rank given to sangheili soldiers who showed great promise. Typically when we think of a shipmaster we immediately think of a sangheili that can handle himself well in a fight but I think it goes deeper than that. I have been thinking about this and have come to the conclusion that a sangheili must show great strength in one of 3 categories before he or she can earn the rank of shipmaster.
The first category- The outstanding fighter
These would be the elites that have proven themselves in many battles by devastating their enemies and coming back home to celebrate after each battle. Though these sangheili would have great combat skill they lack strategic planning and commandings skills. Im putting thel before and a little after he became the arbiter into this category.
Thel trained as a fighter when he was young just like most/if not all sangeili after joining the covenant quickly arose to the rank of shipmaster. After an invasion on one of his ships which he would have been killed if the spartan didn’t leave , truth promoted thel to the rank of supreme commander.
Looking at his past we know that he was responsible for over 1 billion human deaths but we also know that he was responsible for the destruction of a halo ring due to his poor planning, commanding skills, and allowing himself to get booted out of his own ship which is why I put him in this category. I don’t really need to explain what happened with him after that failure cause we already know. We also know how good of a fighter he is as we got to experience him during halo 2 and 3.
The second category- the outstanding leader.
These would be sangheili who have a very good mix of combat skill as well as good planning and commanding skill. They know how to plan for multiple situations, come up with great strategies, and they know how to command their troops in a way that ensures success. These guys are also capable of handling themselves in combat and because of that sometimes choose to go down of the battlefield to fight alongside their men.
They are very good at delivering speeches and words of inspiration that builds the confidence of their troops and gets them ready for battle. I’m sure you guys probably know who I will put into this category but incase you don’t know I am putting Rkas vadum or half jaw into this category. I’m more than positive that I don’t need to explain why I put him in this category.
The third and final category is - the outstanding planner.
These would be the guys who would come up with the best strategies and plans that would ensure them great success and most of the time get them what they want. One outcome would seem like a failure but it didn’t matter to them because they already had planned for many different outcomes.
Despite being trained as a warrior at a young age fighting would not be their strong point and they will tend to have bodyguards around them for protection.Though they lack combat skill they’re great ability to plan and make decisions which brought great results granted the rank of shipmaster. I’m putting jul mdama in this category.
Looking back into jul’s history we can see that during the covenant war he was a shipmaster but I can’t remember if they explained how he got to that rank or not. Anyway a little after the covenant got destroyed the sangheili that opposed the arbiters decision for peace started to rebel which caused a war. Jul being on the side that opposed peace with humans blamed his wifes death on the humans when it was a fact that she died during the sangheili rebellion war and set out on a quest for power which he would attempt to use to destroy humanity.
Afterwards he made a plan to go steal a covenant ship from the servants of abiding truth which he then hid on a planet held oni whi was supplying the abiding truth’s leader with supplies, weapons, vehicle etc. Jul was captured by oni but planned his escape by stealing a ship which he then used to go to a religious sangheili faction which he deceived into following him by acting as a false prophet which is how the storm covenant came into existence.
Anyway back on topic…his planning skills that were displayed during spartan ops was very superb. My guess is that he purposely put that promethian artifact in that location knowing that crimson team would come to claim it and take it back to infinity knowing that some scientists (glassman) would try to examine it which would cause them to get sucked in and brought to his location.
Even though jul had glassman he predicted that halsey would be brought to infinity and already planned ways to convince her to help him… just a note we never seen him fight but we’ve always seen him surrounded by bodyguards which would give me the impression that he is not good at fighting so when faced with some one like locke and his team who are skilled at fighting it makes sense that he would be an easy target to kill…
Im afraid I can’t do a tldr version of this but I congratulate anyone who read it all. ,
Edit: here’s my attempt at a tldr. I’m basically speculating that there are three types of sangheli that could have become shipmaster or higher rank. The warrior-thel, the leader-rkas vadum, and the strategist-jul and I try to explain the strengths and weaknesses of all 3