1. Zombelephants. (Aztecs)-
Nothing short of a tactical nuke will floor these bad boys from what I've played yet.
2. Revenants. (Aztecs)
Sustained crossbow fire, followed by engagement to the front by feudals before cycle-charging your best heavy cavalry the rear.
3. Seraphim. (Papacy)
Ironically, the easiest. Run some light cavalry towards them- if they don't reach there before the bombs drop, chances are they'll wipe themselves out anyway. Keep your army well clear.
4. The four Retainers of Apocalypse; Death, Famine, Plague and War. (Papacy)
Death is the easiest- spearmen engage with their high defense, and charging from behind with cavalry. Famine you need to rush them in large numbers as quickly as possible. Plague are fairly easily dealt with by either running light cavalry round the side or a direct artillery hit. War requires massed spearmen from what I can see, but I haven't come against them yet. Stakes should also work.
5. Heaven's Wrath Mortars. (Mongols)
Run. Very quickly. Away.
Alternatively, three pronged attack of cavalry- one in the middle, two down each flank and hope one of them reaches the rear so you can engage them in melee. Keep your general away from the main brawl.
6. Devils' Tongue Elephants, Elephant Musketeers, Elephant Artillery. (Timurids)
Greek fire works surprisingly well against most of these, especially devils' tongues. Massed spearmen could work less effectively, but still do. Sheer attrition will have to do in many cases, especially as Elephant Artillery and Devil's Tongues can inflict major pain from a distance. Direct artillery hits work as well.
7. Nation Smasher. (Timurids)
Duck and cover while firing, then send cavalry much like against Heaven's Wrath Mortars.
8. Elephant Rocketeer. (Byzantium)
Let them fire while you cover behind something (ANYTHING!) before engaging in melee. Again, greek fire and direct artillery work as well.
9. Not a "super" unit but just as annoying--Mongol Horse Archers/Mongol Heavy Archers (Mongols/Timurids)
In my poland campaign I've been forced to wait out the arrow storm and hope I've got enough spearmen to counter. Straight heavy cavalry charge should distract them far enough to leave your main force to engage the infantry (if you're lucky, and they actually have infantry). Long range artillery and ranged units will handily counter the normal horse archers, but the heavies are a real problem due to their armor and flame arrows.
EDIT: Limited success with Polish nobles followed by Templars also reported. If you can force them into running into circles you can sometimes catch them with cavalry.
Also, Mongol artillery (Rockets, Catapults) you need to engage as quickly as possible, at the expense of any other unit. Do
not approach a rocket launcher solely from the front- at least 2 different directions (3 if protected by horse archers) will be needed to succeed. These things wipe out armies by themselves. The problem is you're mostly on flat battlefields when dealing with these monsters, so buckle up- it's going to be a nasty ride.
And I shall go Softly into the Night Taking my Dreams As will You[This message has been edited by EnemyofJupitor (edited 03-02-2009 @ 11:17 AM).]