Thank you for asking! For those not aware of all the verses I have, there's one where Indran survived the attack by the Jedi. She and Mortis had two additional kids to Caitlin/Aleena, Markus being the youngest.
Indran is powerful, but it is more subtle and persuasive power in the Force than the flashy stuff. She’s capable of that as well if called for, but prefers to keep to her strengths. Thanks to her father’s insistence, she’s also quite capable of wielding a lightsaber and strengthening her physical abilities.
Formal Training - ★★★★1/2
Her parents ensured she’d get into the best schools they could get her into and her training in the Dromund Kaas Academy was extensive. Indran’s also kept up her skills on her own after graduating through different conferences and courses regarding diplomacy.
Despite her talents with a lightsaber, the amount of combat she’s seen is very little. Mostly occasional scuffs when diplomacy has gone wrong is her experience.
Willingness to kill - ★★★★
Despite not having much experience in combat, she’s very willing to kill when it furthers her goals. Preferably quickly and cleanly.
Previous victims - ★/★★★★★
This depends on how one defines what a victim is. If we are talking about people she’s killed, it’s not that many. Some rivals, some Academy scuffles, the usual all Sith engage in. If we are talking about people who’s lives she’s possibly ruined and made worst, and that’s up to interpretation, is the populations of the planets she’s persuaded and/or coerced to join the Empire.
Markus is powerful as one would expect from someone of his lineage. He also does have the training to utilise it to the maximum, but rarely ends in situations where he has to utilise it.
Formal Training - ★★★★1/2
Mortis and Indran definitely pulled all the strings they could to make sure he got the best education. From private tutoring, best schools for human Sith, good group on Korriban, anything they could provide.
Markus has never been in combat. Every experience is classroom based practice than actual combat.
Willingness to kill - ★★★
He’s a Sith, it’s part of the job. He feels no regrets when killing is needed, but not the first solution he goes for.
Only those he’s killed during Korriban education and few rivals. Not a lot of need for him to kill. People he’s helped convict in the totally not biased legal system the Empire has is a bit longer, but he’s still young, so it’s not overly long.