Clearer tidbits and information to the incomplete Pokemon Conquest information in Serebii
Legendaries
General - Except for Arceus and Rayquaza, Legendaries can appear on any story as long as the requirements are met and the Warlords involved are in your control.
Articuno, Mewtwo, Groudon - They only appear after Mitsuhide, Kenshin and Shingen stories are completed respectively. Nixtorm, Illusio, Terraria facilities have to be all at least Level 2 or 3 respectively.
Registeel - You must require at least 15 Warlords with Perfect Links (A Rank 1 Ginchiyo with Luxio counts, but Luxray will not count, a Rank 2 Ginchiyo will count either). Your warriors that does not have Perfect Links cannot exceed 50%, meaning you warriors without Perfect Links should not be more than your Warlords with Perfect Links.
Rayquaza - Appears when all Legendary Pokemon are linked. Reshiram is an exception.
Swarms
They have a higher chance of appearing on areas with level 3 facilities. They are more likely to appear on enemy areas. The probability of swarms decreases every year until 0.
Eevee does not count as a Swarm. They have a chance of appearing when the Hero isn't already possessing an Eevee. Having the Hero in your team does not affect Swarm probability.
Rarer or Stage 1-2 Pokemon
Upgrading the wild areas to Level 2 or 3 will cause them to appear (e.g. Larvesta, Munchlax, Blitzle).
Warlord Evolutions
General - All Warlords except you will not evolve on your main story.
- Use your evolved warlords at least once or you will have to evolve them again.
Masamune and Nobunaga - They only evolve on their own stories.
Nene and Nou - To complete the collection and let them evolve, link and use all Poison and Ghost Pokemon with any Warlord or Warrior.
Mitsuhide - Evolves only after you completed his story. Will not evolve on his story unless already cleared.
Shingen - Evolves only after Kenshin's story is completed.
Kenshin - Evolves only after Shingen's story is completed.
Mitsunari, Kiyomasa, Masanori
Kiyomasa will not appear until you have found Mitsunari's Perfect Link. Masanori will not appear until you have found Kiyomasa's Perfect Link. They can be recruited only on Ieyasu, Ujiyasu, Kanbei, Yoshimoto, Motonari and Hero's stories and can be found on Ignis, Fontaine and Greenleaf respectively.
Pokemon that evolves by Trading
Warlords/warriors with these Pokemon has to deal the final blow on an enemy warrior (neutral or enemy) and they have to satisfy the recruiting conditions (4 turns, Super Effective, or the unit dealt no damage to your team).
Recruiting Warlords
Not only they have to satisfy the Warrior recruiting conditions, they must be dealt the final hit by your Warlord. Obviously famous people won't join you if you send cheapskates to ask them to.
Wild Pokemon and Neutral Warlords/Warriors
Their link percentage are scaled to the average of your total army link percentage. If you want wild Pokemon or recruit warlords with higher links, use warlords/warriors with higher link percentage. That way, you can grind less to evolve or just strengthen your forces. For example, using an army force with an average of 9% link recruits warriors with 7-8% link and pokemon with 4-5% link. An army force with 50% average will recruit warriors with 48% link and wild pokemon with 44-45% link. Do note that enemy warlords/warriors do not scale to your army when recruited, so if you are not bothered to level up that Yukimara with a 5% link Charizard and want a higher link instead, recruit him on the wild instead.
Upgrading Facilities
The amount of experience points a facility gains equal to Total Warlord/Warrior's wisdom x Amount of gold invested. Using 6 Warlords and invest 2000 gold is more efficient than 2000 gold per Warlord. Special buildings appear when all the initial facilities are at least level 2.
Warlord Stats
These are used out of combat. Power is used for mining, Charisma is used for shops, alchemy and blacksmiths, Wisdom is used for upgrading.
Events
Professor - I hate him. End of story. Comes every May-July, 1st year just to repeat the same thing every single time to make you annoyed and have the strong urge to stab his eyes out.
Travelling Merchant - sells the ever-beloved Guardian Charm, various evolution items, Fireworks and other mostly ignorable stuff.
Farmer's Request - They will ask for a sum of money, with rewards in return.
Weather - Maximizes Ice, Fire or Water Pokemon's energy on affected castles.
Bored Warlords - If you haven't fought actively for a whole year, they will complain about no war(geebus I thought you guys wanted peace throughout Ransei), and a random farmer will show up to give random ignorable items. This doesn't cause them to leave if you're worried.
Gabite Officer - That One Guy. Most people wanted him marinated, skewered, barbequed and served on Queen Elizabeth's 55k pound platinum dinner set. This event triggers when you have conquered 50% or more of the region and you pass the next month. When this happens, enemy areas adjacent to yours will have their entire area increase in power by 200 more than the highest power of one Warlord/Warrior you have adjacent to the enemy area.
Minor Warlord's Attention - Only happens on Minor Warlord stories, all the enemy Warlords will have their army's power increases by a bit more than their initial force. Pretty much ignorable compared to the Gabite Officer.
Bandits - Successfully helping the victims will reward you with a Travelling Merchant item. The mob always consist of a team with Steelix, Gyarados, Scyther, Galvantula, Skorupi and Scraggy.
Warlord's Trip - If your Major Warlord and his/her warlords under his/her castle isn't moving anywhere and is idle for half a year and more, one of your warlords under your castle will ask for your permission of absence for 3-6 months. If you allow, they will be unusable for that period, but will give you a Travelling Merchant item in return and their link will increase by 10-15%.
Four Guardians - a.k.a. your personal Elite Four. They just won't leave, forever, after they are picked.
Eevee - This event may and only may trigger when you have the Hero in your control and he/she does not have an unevolved Eevee in his/her team.
Tips
Guardian Charm is a game-breaking item useful for link grinding. Leave one Warlord that you want to grind on an adjacent enemy area. The enemy will likely invade your area with the lone Warlord. Depending on the enemy army size, the link percentage increases between 2-8% every round.
Items you buy from the wandering merchant and created from the blacksmith/alchemist are carried over between stories, except for Fireworks, Hayfever Pills and Cold Medicine, as they are event items used to raise Energy of all Warlords you possess.
Even if you are grinding Electric, Psychic, Fire, Water, Normal, Ground, Poison or Ghost Warlords and the enemy has immunity to it (Ground/Volt Absorb/Motor Drive, Dark, Flash Fire/Flame Boost, Water Absorb, Ghost, Flying, Steel, Normal), kiting and surviving the enemy until time's up will be a victory for you, as long as you are the defender.
Do remember to delegate every castle that has warlords/warriors, 2 months of doing nothing will cause them to be unhappy, 2 more months will cause them to quit.
You can ask me anything that I didn't cover here, I'd probably be able to answer it.
P.S. I don't know if people are allowed to edit that page. You know what I'm talking about.
