Lysia Plaid (From what I guess from this chapter) CK3 traits chart:
Calm: +1 Diplomacy, +1 Intrigue, +10% Stress loss, +10% Scheme Discovery chance, +50% Dread decay, +10 Same trait opinion, −10 Opposite trait opinion
Ambitious: +1 Diplomacy, +1 Martial, +1 Stewardship, +1 Intrigue, +1 Learning, +1 Prowess, +25% Stress gain, −15 Opinion of Liege, −15 Same trait opinion, Stress gain through gifting titles or granting Vassals independence
Gregarious: +2 Diplomacy, +5 Attraction opinion, +15% Personal Scheme Power, +10 Same trait opinion, Stress loss through Feasting
Genius: +5 Diplomacy, +5 Martial, +5 Stewardship, +5 Intrigue, +5 Learning, +30% Monthly Lifestyle Experience
Beautiful: +3 Diplomacy, +30 Attraction opinion, +30% Fertility, Slower Portrait Aging
Shrewd: +2 Diplomacy, +2 Martial, +2 Stewardship, +2 Intrigue, +2 Learning
Grey Eminence: +8 Diplomacy, +40% Monthly Skill Lifestyle Experience
In a nutshell, she's the best diplomatic character one could ask to produce in the game