Player Units in SRPG Studio may gain skills at particular level thresholds.
However, what if you have a Player Unit who promotes to High Lord at Level 20, and a Skill you want them to obtain when they reach Level 5 as a High Lord?
It might seem hopeless because that's not possible with the "Skills Learned" feature in the Unit database. However, you can utilize Map Common Events.

1. Create a Map Common event that is of the type "Auto Event". The Order should not matter - it can be First or Last.
2. Add the activation condition "Unit" and select the Player Unit this is for.
3. For "Life Condition", set it to Alive.
4. Under "Parameter Conditions", set Level to 5. Utilize the "Equal" setting.
5. Now click "Data Conditions" and go to the "Role" tab.
6. Check "High".

Now, as long as the class is the "High", which you set in the Class Database, an event will play when the Player Unit reaches Level 5 as a promoted class.
You can make it more specific by specifying the exact "High Lord" class, if you either want or need to do so.

If you're worried about players accidentally skipping this skill, you can set the Level under Parameter Conditions up to use the "or More" setting.
That way, even if a unit levels up using Bonus EXP, the next time they load a map they will obtain the skill
Alternatively, you may wish to utilize Base Events that mirror this effect if it does not trigger for you.