Greetings!
Without knowing how the skills system would work, I'm going to propose basic skills and some "specialized" ones, since having them all would be too strong.
As I have answered in my previous post, I would give the assassin the possibility of specializing in a type of continuous combat, fast (hit and run) or mixed (hit melee, move away, hit mid-range and rotate between these styles).
This would mean that I would have to have a balanced skill kit but would have to sacrifice some of the aspects to enhance another. How to do it? It would depend on whether you want to use talents, pigeonhole it as a specialization or directly give each skill a specialization that "improves" the skill in that field.
The "basic" skills would be obtained regardless of the specialization thus making their basic kit but these would be enhanced if you choose that specialization then they would obtain the "special" specialization skills:
Direct Combat Skills:
-- BASIC:
- Combo hits. (Each consecutive hit in a short period of time deals more damage than the previous one.)
- Break armor. (You hit, subtracting armor from the target)
- Disable limb. (You disable the target's arms by disarming them.)
- Somersault (A small jump to avoid areas).
- Low blow (Cuts the casting of skills).
-- SPECIALIZATION:
- Passive: Boost combo attacks, boosting your damage the more consecutive hits to the same target.
- Final blow (Consumes all your combo points to cause a super powerful attack).
This specialization encourages you to maintain direct combat and not run away after hitting, but due to the little armor you must move well and dodge as much as possible.
Assassination Combat Skills:
-- BASIC:
- Stab (Causes a lot of damage from the target's rear arc).
- Cut Throat (From stealth... Deals damage and silences the target for a period of time.)
- Stealth (You enter invisibility).
- Distraction (You make enemies look away and you can go through their back).
- Smoke bomb (You disappear into the smoke).
- Evade (Allows you to evade the next attacks).
-- SPECIALIZATION:
- Passive: Boosts your attacks from behind and your attacks from stealth, giving it an additional effect.
- Assassination (Attack with a powerful strike from stealth if it kills, jump back and stealth again). Long-playing CDs.
- Sprint (Gives you great speed to run away and re-enter a fight).
These abilities propel you to attack and move being very deadly against a single target and wreaking havoc.
Mixed Combat Skills:
-- BASIC:
- Poisoned Strike (You use poison to cause an adverse effect on your next attack).
- Grenade (Throw a grenade that affects enemies in an area, the effect).
- Cover shot (Causes little damage but takes you a few meters away from the target).
- Shoot (Several throwing spears in the same attack at a short distance in an area).
- Murderous charge (You launch yourself at the target, hit him and place yourself on his back).
-- SPECIALIZATIONS:
- Passive that can rotate: (can never be activated twice in a row and cannot be activated until the activated effect ends).
-> Ninja Assassin: When activated, increases your ranged damage for a few seconds.
-> Grenadier: When activated, increases the damage of your grenades and reduces the CD of abilities for a few seconds.
-> Deadly Assassin: When activated, increases the damage of your melee attacks and reduces the damage taken during that time.
This specialization enhances the mixed use of the basic abilities of the three specializations by having the player follow a rotation to take their damage to very high levels.
These are a couple of examples of abilities, but I think I've managed to explain a style/mecha with abilities that the assassin could have.
I know I've been moved by this post and I think I've put more than I really asked... I just... I've let my imagination run wild. All the best.