Digidestined: ("Chosen Children")
https://www.youtube.com/watch?v=mUihzNN0ees
https://www.youtube.com/watch?v=1GTJWgBbP04 (Digidestined Evolution)
https://www.youtube.com/watch?v=miat7VvLZys (Fusion of Fate, Spirit Evolution)
Fated to save the world, go through an adventure or at the very least be held in some importance to the Digital World. Digidestined carry around "crests" given to them, somehow, from birth. These crests allow them to access "Ultimate" Digivolution much, much earlier (almost the second they get Champion) and show them to be a fated Digidestined. As the fated "Chosen Children" they have the closest bond to their partners and even have the ability to access "Spirit Evolution" and exceed their beginning state. Meaning, even if their Digimon can only go Rookie, they can fuse with their Digimon and jump straight to Champion, combining their powers; united as one. Their most interesting ability is the power to access "Armor Evolution" through the use of special fated eggs, which allows their Digimon to Digivolve to a state even while in a corrupted area or quadrant. Their main weakness though is their lack of "Digimon Cards" and "Digi-Soul" - therefore rendering them a normal human outside of their partner.
Digimon Tamer ("Chosen by Nobody")
https://www.youtube.com/watch?v=bueeN9lMe0g
https://www.youtube.com/watch?v=IjU8gmRdgaQ (Tamer Evolution)
https://www.youtube.com/watch?v=Tak5XoMPPA8 (Human Data-Absorb, Biomerge Digivolution)
Known to be "ignored by fate" and made a Tamer either due to sheer luck, or chance. These are known as 'Digidestined' who were never meant to be one in the first place. They have no goal, or quest. Or crest for that matter. They do however have an Advanced Digivice which allows the use of tools simply known as "Digimon Cards" throughout the human world. Digimon, being made out of data, can be modified through the use of these 'data cards' with a simple scan through the Digivice. Of course, in the human world these "cards" are little more than toys. Tools to collect and play with. Yet in the hands of a tamer they allow a Digimon to gain extra abilities, boosts and other such advantages with a quick, simple scan. Using a card, however, burns the card up. Meaning these powers depend completely on how many the Tamer has, and if the Digimon can take this boost. The greatest power and weakness that a 'Tamer Digimon' has however, is Absorbing Data. Digimon 'born' to a Tamer has no 'Fate' and therefore no true 'fate to power' as a hero, but, like wild Digimon, they can kill and absorb a Digimon to 'increase' their own data. Allowing them to grow, Digivolve further and more. The main weakness to a Tamer however, is their lack of crest, "Digi-Soul" and because of their 'lack of fate' cannot use Armor Evolution.
Digimon Guardian ("Chosen by DATS/Data Squad")
https://www.youtube.com/watch?v=x246fAqPjYo
https://www.youtube.com/watch?v=7v7M9T14tq0 (Squad Evolution)
https://www.youtube.com/watch?v=cilyZGQh5aE (True Digi-Soul, Burst Mode)
Digidestined are chosen by fate. Digimon Tamers are ignored by fate. Digimon Guardians, also known as DATS Tamers, are people who were once one of these things, but denied them. They refused to allow fate to dictate their motives, refused to be a hero or villain, or even threw away their Digivice. Through the use of human technology, the organisation known as DATS recruited these 'lost souls' and gave them tools. Equipped with a brand new Digivice designed to draw out their 'Digi-Soul' from within them. Digi-Soul is a power all Tamers/Destined have, but one that can only be brought out by a Guardian. By doing so they lose the instinctive ability to Digivolve their partner through fate, and absorbing dead Data, but instead gain the ability to 'draw out' power by physically fighting Digimon, either with their fists, weapons, or so-forth. This gives them enhanced physical abilities beyond the normal human to such a point that, while their putting their lives on the line, they can help their Digimon far more than other Tamers. Guardians are under strict focus by DATS however, meaning that the only way to become one and get the special tools is to join them. Going rouge? Think again. The main weakness of these "denying fate" Tamers is that they lose pretty much everything in return. Armor Evolution, Absorb, Card Slashing, etc.