From Bulbapedia, the community-driven Pokémon encyclopedia.
(Attempt to prove the mess of legendary groups can be organised properly. wip.)
Most legendary Pokémon are part of a group.
There are groups in which members share an equal amount of similarities (no member sticks out or has exclusive features, unless they all do with the same impact **)
and there is usually an additional special member, which sometimes takes a master/guardian like role, and is in some way related to the group.
Groups share a combination of many of the following traits ("+"-always the case):
- +specific method of encounter*
- +released in same generation
- +next to each other in pokedex order*
- +same stat total
- +secondary type, if any
- +similar learnsets (same levels, shared minor moves, comparable moves, especially STAB)
- +shared mythological background or origin story, if any
- -most cases even having exact same individual stat numbers in varying order
- -similarly working ability
- -similar design basis
- -main type
The additional members might share several of the above traits with their group, but always have some clearly superior traits or exclusive features.
Some masters might be part of a group of their own league.
- *There can be a few deviations in the case of version mascots (because of later releases of the third version) such as small dex-gaps and the final appearance being kept secret.
- **An exception is Suicune, who starred as the version mascot of Crystal due to lack of fitting candidates.
Most famous kind of legendary group, with 3 equally similar and equally contrasting members. These are the first legendaries to appear in each generation and have 580 total base stats
Generation IV was the "ultimate" generation, hence why instead of the usual trio, the version mascots themselves were a proper trio, meeting most requirements and of course having 680 total stats instead of just 580. These were accompanied by a sub-trio of all Psychic-type legendaries relevant to their plot, with matching colours. The traits of each Lake guardian (what they represent/method of obtaining/distribution of stats) seem to be based on the trios of the preceeding three generations (Birds - Azelf, Beasts - Mesprit, Golems - Uxie)
Giratina underwent a change with the release of its Platinum version, gaining a forme with altered stats, look, and ability.
There are duos of rather minor importance, with 580/600 total base stats.
And Version mascot duos, with the higher 670/680 total base stats.
There also exist imbalanced duos, each consisting of a parent and a child.
The first represents creation of life through artificial means (cloning), with the result being a stronger creature.
while the second represents creation of life through natural means (breeding), with the result being a weaker version of the original.
In both cases, the original actually appears after the child in the pokedex.
Additional group members
Some legendary Pokémon are extra members of a lesser legendary group. For several of them, enabling an encounter requires the player to have obtained its complete group.
They can be superior, with a master-like role, a fourth hidden member, or even a weaker counterpart to members of a legendary group.
They were covered above, but this time the emphasis is on them.
Most generations introduced a standalone fairy-like event-Pokémon, with every base stats being 100. Note that Mew and Manaphy completely fit into this category, but are much more importantly additionally related to another pokemon each.
Everyone except for 4 legendaries have been covered above. These 4 are similar to the ones in the minor Duos, powerful unique pokemon with interesting backstories/origins except they don't have a counterpart. They are hidden/extra legendaries towards the end of the dex (all event-pokemon or in the case of Heatran, not in a regional pokedex).
Main legendary trio type analysis.
This relates to the true legendary trios, of which we get one each generation (except for the ultimate generation: IV, where there was a mascot trio and a full psy sub-trio instead.).
Meaning the first groups on the list above.
Most of the time, people don't give it much thought, and think that the first 2 trios were following a "traditional trio" type, but then went to random on from golems.
After a serious look, you can notice something interesting.
First you have to realise that there was a change from genI to genII, just like any other generation.
It went from
Ice Electric Fire
Electric Fire Water
Meaning? They always change 1 or 2 of the types, so it doesn't repeat and stays fresh for as long as 10 generations.
For now they seem to reuse each type until it appears twice.
So the third trio (golems) made another use of the Ice type that was exchanged for Water in the second one.
Rock Ice Steel
But in this situation, they now had the same thing as in generation I, Ice to replace with something fresh, and 2 that can be repeated.
Steel Rock Grass
One could speculate on future trio types from this, but the only thing that seems completely certain, is that the Water type will be used a second time, and the other 2 will both be fresh.
Although with 7 types being used already, 2 have been used for secondary types (Flying, Fighting) and Normal being obviously out of question, it actually narrows it down to 7:
Ground Poison Psychic Bug Dragon Ghost Dark
Several of these could easily be used for more secondary types on trios though.
Ground seems the most "elemental" out of these, so its chances are above average.
Curious about whether they can really pull off a few more working trios with types like these, or if they will start from scratch soon.
Eeveelution moveset improvement
This is only part of my fakemon project, cause I love bulbapedias tables :E
My personal improvements of eeveelution learnsets, including a hypothetical wind element based final evolution.