Game Systems and Design

Stellar concerns is a hodgepodge game specifically it is divided between two game systems. When out of mechs players will be using a reskin of D&D 5e while in meches we will be using the Lancer RPG ruleset for all in of mech mechanics. You can find the core rulebook for free by looking up Lancer RPG on google. all mechanics dealing with out of mech systems will be ignored. Some Lancer mechanics may be changed to allow for this fusion. Meanwhile all D&D mechanics are immediately suspended once inside the Lancer Mobile Platforms. I.E. your D&D intelligence score will not govern anything while inside the lancer. Basically no hot swapping rulesets. 

for level progression see Leveling Up Character and your Lancer and for more about the lore of the mech see the Lancer RPG core book and the Lancer Mobile Platforms page when it's finished.