Seraphimon is a wise digital sage who fights for the side of good against the forces of evil. He is known particularly for the creation of the DigiDestined.
Details of Seraphimon's origin, youth in the Digital World, & his emergence as a champion of good are unknown canonically.
Sometime eight to ten thousand DigiYears ago, Lilithmon sought to conquer many worlds in the universe. Among the opposition was Seraphimon. War broke out between Seraphimon & the factions of Lilithmon. This war stretched for 2,000 DigiYears & across countless planets. Many of Seraphimon's warriors perished in battle with Lilithmon's minions, such as DarkKnightmon.
Sometime during the conflict, Lilithmon entered into service to the great Tactimon, who assigned her to conquer Earth. She & her henchmen occupied a palace on Earth's Moon, located directly above the location of the powerful Zeo Crystal. It was also during this period that Seraphimon discovered five DigiMemories & a map to the Desert of Despair. It was also known that Lilithmon came into the possession of a sixth DigiMemory, the Core Dagger, & Coredramon, through unknown means.
In the closing days of the war, Seraphimon came close to victory. In desperation, Lilithmon lured Seraphimon to meet, with a promise of peace. However, this was a trap. Lilithmon banished Seraphimon into a time warp in which he existed outside normal time & would eventually communicate via a tube. Seraphimon, however, managed to seal Lilithmon & her minions into a space dumpster where they were to reside for eternity -- until being discovered in the future on a drifting planetoid.
Seraphimon knew that Lilithmon may one day return & continue her war on Earth. In preparation, Seraphimon constructed a base of operations known as the Command Center in the Tokyo mountains & used it to stage the creation of the DigiDestined. It is probable that around this time he befriended a young robot Digimon named Kokuwamon.
When Lilithmon is released in the future, Seraphimon, now only appearing as a large figurine in a blue tower of light, asks Kokuwamon to find five "teenagers with attitude", thus creating the first generation of the DigiDestined. Taylor, Carly, Maggie, Spencer, & Nicky are chosen. Each DigiDestined receive a digivice - one with each of the five DigiMemories used in the coin toss that decided the fate of the Digital World eons ago, & thus Seraphimon creates his team of the DigiDestined.
When Alex becomes the evil DigiDestined with the sixth digivice received from Lilithmon, he sabotages the Command Center & disrupts the link to Seraphimon. After much turmoil, Kokuwamon reestablishes the link & Seraphimon helps the DigiDestined stop Alex's evil rampage. Once the evil spell on Alex is broken, Seraphimon accepts the new DigiDestined with open arms, even giving him an enormous amount of his own energy to give him Coredramon again so he can retrieve the stolen digivices. When those powers run dry, he gives him Baihumon. When Tactimon banishes Lilithmon & begins his own conquest for Earth, Seraphimon digivolves the DigiDestined's Digimon into the Thunder Digimon.
In the episode The Wannabe DigiDestined, Seraphimon de-ionizes - or powers down - due to the planets aligning.
As time goes on, Seraphimon will see off four of his original DigiDestined. Taylor, Carly, & Spencer are asked to attend a peace conference in Switzerland, & are replaced by three friends the DigiDestined make (& save), Cody, Zoe, & Liam. When Maggie decides to move to China to focus on her gymnastics, she chooses Mia, a girl who had been used by Lilithmon & Tactimon for evil purposes, as her replacement. Though Seraphimon is sad to see his former DigiDestined leave, he gladly accepts each of the new DigiDestined & wishes the previous ones well on their futures.
Seraphimon senses the return of Oozemon, a demonic Digimon of unparalleled evil that he banished years ago. He quickly summons the DigiDestined & informs them of the direness of the situation. When the DigiDestined fail to stop Oozemon from being released from his Hyperlock Chamber (by Tactimon), they fight his DemiOozemon.
During the battle, Oozemon makes his way to the Command Center & destroys it, smashing Seraphimon's time warp in the process. Seraphimon then begins to age rapidly. The DigiDestined travel to the dimension Phaedos in the Digital World, where, with the help of Master Warrior Mervamon, they obtain a legendary Great Power. After destroying Oozemon, the DigiDestined go back to the Command Center, only to find out that Seraphimon has already passed. However, using the Great Power, they manage to bring him back to life, restoring his energy tube & the Command Center in the process.