Baraqiel initially hated Issei due to his misconception about him being an Oppai Dragon and taking advantage of his daughter. After the battle against Loki, Baraqiel starts to have a change in view on Issei, even asking him to protect Akeno on his behalf.
In Volume 22, Baraqiel was shocked to learn of Issei's true feelings for Akeno after he was depressed in thinking Issei chose Rias over his daughter, Akeno and that her happiness would cease, however, he came to completely trust in Issei's love for her and broke down crying commenting to his deceased wife, Shuri, that their daughter has found a good man.
Baraqiel loves his daughter very dearly and is fiercely overprotective of her. Baraqiel also held strong guilt and remorse for his failure to protect her mother as he said nothing to rebuke whenever Akeno pointed out his inability to protect Shuri before they reconcile.
In Volume 22, he became truly happy for his daughter's happiness in that she has a found a good man in Issei.
Baraqiel and Azazel have a close friendship. Azazel feels guilty to Baraqiel for making him leave his family which resulted in the death of his wife and strained his relationship with his daughter. Despite this, Baraqiel doesn't bear any grudge against Azazel and still treats Azazel as his good friend.
Baraqiel loved his wife very much. When they first met, Shuri nursed him back to health from the injuries that he sustained from fighting enemy forces. They deepened their relationship and eventually had Akeno. Together, the three of them had a quiet lifestyle until Shuri was tragically killed in her attempt to protect Akeno, claiming that she was an "important and precious daughter of that person". She returns as an apparition in Volume 7, encouraging her daughter to reconcile with Baraqiel, as she knows that he greatly loves and cares for them.