- In Volume 1, Asia dying in Issei's arms after having her Sacred Gear stolen, and thanking Issei for being her only friend. His following rampage against Raynare, her murderer, is just as tragic.
- In the anime, Issei desperately prays to God as she dies.
- Koneko's background: Her master is killed by her sister, who then abandons her to die supposedly. Thankfully, she was picked up by Sirzechs, who gave her to Rias.
- In a way, Kuroka had it worse. She left her sister to keep her from becoming a fallen, and when she finally had the confidence to take her back, Issei, thinking she would hurt Koneko, almost killed her. Ouch.
- Akeno lost her mother, and blamed her father for years, effectively leaving her an orphan. Until Issei and the Oppai God came along.
- Kiba's past involves him and his companions subjected in a harsh environment to be able to wield a holy sword while believing in God. They all died except for him who was also succumbing to poison and only wished revenge.
- The scene of him reaching Balance Breaker state in Episode 5 of Season 2 was done really well, the script, the melancholy music that is playing at the background, has put almost everyone in that area in tears. The ones who are not are Freed, Balba, Kokabiel and Xenovia, who is a stoic at that stage of the story.
- Issei's death in Volume 11. Hell, just Kiba's Wham Line "That day, we lost Issei-kun." can still have this effect.
- Not only Issei's death but the lead up to his death. Before he died he had just taken down Sairaorg and cemented himself as a hero in the devil world. His power had grew from a dirt-level devil to one that even a Satan could have trouble taking on. Not only that but he had just gotten promoted to mid class devil and judging from Azazel and Sirzechs' talk it won't be long before he becomes a high-class devil. Meaning his dream of starting his own harem wasn't a dream anymore. He also had heartwarming interactions with his friends such as calling Kiba his best friend and promising to marry Koneko in the future. To top it of he finally started dating Rias something which he had always wanted. When factoring in all his accomplishments, relationships and his future his death really is tragic especially since his death came out of nowhere. Long story short, the Diabolus ex Machina hits Issei, and hits HARD.
- The prologue to vol. 12 takes it Up to Eleven. It's set a few days after Issei's death. Ravel and Koneko are both trying desperately (and failing miserably) to contain their sadness, and end up crying in each others' arms. And they are the best off of the group. Kiba is verging into Stepford Smiler territory as he desperately fights to hold the group together. Akeno is in an Angst Coma, seeming more dead than alive. Asia wants to kill herself to follow Issei, only stopping because it isn't what he would want. And Rias essentially says that the world can burn for all she cares, if Issei isn't with her.
- Sairaorg's past involves discrimination. That is all.
- As revealed in Volume 9, there are those who followed Cao Cao because he gave them a reason to live instead of being feared by their own peers because of their abnormal Sacred Gear powers. Issei even gets to think of Asia's life during the time she was a human with her Twilight Healing and that those who have Sacred Gears as a human didn't really have a good life.
- In volume 12, the past possessors of Boosted Gear sacrifice their lives to stop Samael's curse while singing the Oppai Dragon song. Normally it's funny, but somehow it's tear-jerking since they all sacrificed their lives and existences for Issei's will. Even Issei was silent about it.
- Ddraig almost manages to pull off one when he reveals that in order to maintain Issei's soul while his new body was being remade, he had to use his spiritual powers and that he's about to run out soon. Issei was almost about to cry at having his closest partner departing from him until Ophis tells Issei that Ddraig's just sleeping. With a loud snore coming from Ddraig.
- When Issei and Akeno visit the Grigori institute, Issei sees a wall full of paintings of people. When asked who they were, Azazel told him that it was a painting full of his old comrades who had died in the war and from other reasons. Considering Azazel's hundreds of years old, he must have seen a lot of deaths in his entire life.
- In volume 12, Kiba battles Georg of the Khaos Brigade. Losing badly and about to face his own death, Kiba and the demoralized Gremory Group hear Ise's voice encouraging them to look after his best pal. One of Ise's Evil Pieces transforms into Ascalon and allows Kiba to win the fight. Apparently even beyond the grave, Ise cares for his friends. A mixture of tear-jerker and heatwarming since at the time no one was sure that Ise was ever coming back.
- Valerie's last words to Gasper before she falls into a coma. To say Gasper was devastated that his best friend is going away from him would bring tears to anyone's eyes.
- The entire Star-Crossed Lovers story between a devil and a devil-hunter before The Alliance was formed in volume 18. Issei even ponders on it as it could have happened to him and any person in his harem.
- Volume 19 is abound of this, in particular how Strada addressed the DXD team after his defeat. To elaborate:
Neither I nor my comrades who were lost for words, could do anything but shed tears for their reunion. …Kiba, it’s truly great. What you’ve lived for until now, it exists! Because you’ve lived until now, you were able to see this girl again!When Kiba spoke — as if possessed by something, he seemed to have a gentle expression. …To become a sheath to this guy that I’ve always been concerned aboutnote . Kiba had said that he was determined to protect her forever.
- He gives Asia letters from people she cured with her powers during the time she was still a nun. When she was excommunicated and sent to Kuou Town, Strada tried to reach her to give the letters with no avail, knowing full well that the people's honest confession and testament from the letters would make at least dampen her punishment and he wanted to help and put her under his protection.
- Kiba's reunion with the Holy Sword Experiment survivor, Tosca, that's all. Even Issei narrated that all the team can do is crying as they watch the heart-wrenching event unfolds and he analogues her for being a sheath for his best friend.
- He gives Azazel, and in extension Gasper, a fragment of the genuine Holy Grail, with later Valerie's subsequent awakening and reunion. Damn you Strada, if all men can follow your example, the world will become a better place in no time.
- Meta example: Ishibumi's mom died while he was writing volume 20. Considering the events of that volume, it's a lot more heart wrenching than what it should be.
- To elaborate on volume 20, Belial and Rizevem hold Issei's parents hostage. When he makes it there, he gets bound and forced to drink dragons blood by Belial, forcing his true nature as a dragon to be shown in front of his parents, reducing him to a sobbing wreck. Yet his parents don't hate him, and hug him. This causes his Bilingual to work its magic on Issei's parents. It shows their past, revealing that Issei had two other siblings that were tragic miscarriages before him. However, his parents persevered, learning from them instead of giving up, and finally had him. As more of Issei's childhood is revealed, it's revealed that the main reason for his inferiority complex is that he feels responsible for taking his dad's fishing pole without permission and when he breaks it, he feels like it's his fault. It's a partial catalyst to why he is so obsessed with Oppai; to keep his inferiority complex in the back of his head, while being genuine about his love of Oppai all the same. All of this is punctuated by his parents not caring if Issei is a dragon, and that if he was just a mindless monster, he wouldn't have felt fear of rejection. The inflections in his dragon voice were still those of their little boy, scared of what was happening to him in front of them. Damn.
- According to the timeline of Highschool DXD EX Instead of spending time with his harem and his kids, Issei is frequently called away to help with the problems of various mythologies. This results in him having little to no involvement in the lives of his own family and having his children be raised mostly by Vali and Kiba, and at least one of them resents him for it.
- Course the same kids refer to Issei's wives as keeping him on a tight leash, so it may be that just how often he is away from them is exaggerated for the sake of drawing attention to the one kid's resentment.
- The fact that Issei's kids refer to Azazel as the "Founding Governor" suggests that Azazel died sometime later, considering the events of Volume 21...
Tear Jerker / High School D×D
As much as this series has a lot of funny moments and fanservice, there are also genuine scenes that will make you cry.