Their relationship hasn't been shown clearly, but judging from Enma's anger and reaction when he fought Tsuna and cried at him to give her back as well as when Enma dreamt about her as he kept calling her name, it can be implied that Enma loved her very much and shared close relationship with her.
Their relationship hasn't been shown clearly, but Enma also seems to care about his parents and was extremely upset because of their death along with his sister, Mami, as shown from his anger and reaction when Enma revealed to Tsuna that his father killed them.
Enma is normally seen taking orders from her even though he is the Simon boss. However, Adelheid seemes to genuinely care for Enma as seen when she becomes concerned about him when he becomes depressed about Large's loss, when Enma almost kills Tsuna, and when Enma lies on his bed while he kept calling his sister's name. Adelheid accompanied him and assured him that she understood his feelings and promised that she would purge the Vongola.
Large is devoted and loyal to Enma. So far, he's the only member that truly regards Enma as the boss of the Famiglia, commenting that he has strong eyes. Enma himself also cares for Large, since he's the very first person to be upset and agitated when Large lost and was taken to Vindice Prison.
Kouyou seems to have little to no respect for Enma even though he is the Boss of the Simon Famiglia. He also frequently makes fun of Enma, calling him "Loser Enma". Despite this, Kouyou is actually cares for Enma and have faith in him to lead their Famiglia back to its glory. Enma also hold him dear as seen when he mentioned his name along with other's names who are precious to him before his fight with Tsuna.
Enma held deep hatred for Demon for manipulating him and his Guardians to fight against Tsuna and his Family and set a trap for Cozzato that led to Simon Famiglia's isolation and persecution for years. Demon viewed Enma and his Guardians as merely one of his tools and weapons to create the Vongola Famiglia that he desired and was apathetic of their sufferings. Enma's hatred was deepened when Demon revealed that he was the one who killed his parents and sister, angrily stating that he will never forgive him. However, upon knowing Demon Spade's real reason to gone that far, Enma seemed to symphatize him.
Tsuna is similar to Enma, as they were both said to be "no-good" and "losers", as well as being the unwilling tenth Boss of their respective Famiglias. Their friendship once was strained when Enma thought that Tsuna had lied to him and his father killed his parents and sister, to the point that he nearly killed Tsuna because of Demon Spade's scheme. However, despite all the stressful situation their relationship has been through, they remain excellent friends, similar to Giotto and Cozzato's relationship. This is evidenced by Enma's confidence that Tsuna would never betray him, and Tsuna's devotion to Enma's safety.
Unlike others, Enma treats Skull nicely and agrees to help him despite just known him for short times. He even asked his Guardians to become Skull's representatives (even though he, at first, didn't understand it) and when they refused to, he's the only who willingly to become Skull's representative. So far, he's the first person who doesn't look down on Skull and care for his well-being as shown when he fought Varia. When Adelheid angry at Skull for dragging Enma into danger, Enma quickly came to Skull's defense, saying that Skull's is a good person and grateful that he had saved him. Skull has been shown seemingly ordering Enma around since he's his representative, but also showed concern for him and even protected him when he was about to be killed by Varia.