A cold and distant kind of man. He's very strict when it comes to Asbel and matters regarding the Lordship and tradition. Despite his harsh exterior, sometimes he's capable of properly showing love. He equates loving flowers to loving people.
Aston is the youngest of two brothers fathered by Albert Lhant. Per tradition, inheritance of the Lhant Lordship would've gone to his older brother Aldan. However, for reasons unknown, Albert chose him instead.
Due to this sudden and surprising decision, Aldan and Aston began to argue fiercely, resulting in Aldan being banished from Lhant and sometime afterwards dying without resolving anything with Aston. This left Aston with a sense of anxiety regarding the process of inheritance and this anxiety carried on into when his children were born and became projected onto them.
20 years before the Main Arc, he met Kerri who came to Lhant due to being politically married out by her family. At the time, Aston was very into gardening and taking care of flowers, so when Kerri first arrived she mistook him for a simple gardener rather than the Lord.
When Kerri found out, she was furious of course, but mostly because of her situation of being in a forced marriage. Aston then tells her to "learn to love the flowers" before leaving, which confuses Kerri and just serves to make her more mad. Shortly afterwards, he's called to go to battle during one of the numerous border skirmishes with Fendel. He initially doesn't expect Kerri to still be there when he gets back, but she is. Sometime after that was when they got married.
 In the Story
During the course of the story, Aston did many questionable things that contributed to Asbel and Hubert's current situations and life paths. For one, because of his anxiety with the inheritance process, his feelings regarding his brother and the circumstances of what happened between them to be projected onto his sons. This projection of his own feelings caused him to be blinded to the personalities of his sons and the fact that his youngest wasn't even remotely interested in the title or position. Because of that, he made the decision to adopt Hubert out of the family to the Oswells as his idea of the "best possible action" because he was afraid of his sons fighting over the title and position like his brother and he had.
This action spectacularly backfired on him as it caused Hubert--who hadn't even considered wanting the title or position--to become spiteful towards his original family and Asbel to run away and join the Knights. The spite his actions instilled in Hubert eventually ended up with Hubert taking the title and position from Asbel and banishing Asbel for a time from Lhant anyway. Despite his best efforts, Aston's actions only resulted in karmic justice and he died before he ever saw Asbel or Hubert again since their childhood.