I think the Kataphracts are better than the Serpent Riders imop

Serpent riders are definitely better. If you play your cavalry well, they shouldn't get shot to pieces, and with no volley and the new (closer) set up, you should be in combat fairly quickly. All that to say, defence is not the most important stat.

For cavalry to work they need to
1. get the charge
2. win the fight
3. actually kill their one/two opponents


For 1 terror or a hero with might is needed. For 2, high fight (at least 4 is good). For 3 a lance, or at least strength four.

From this I can say that kataphracts are not that great. They don't have the high fight, or lances, or strength four. (sure you can upgrade them, but then they're more expensive...) The armoured horses are the biggest draw for me, but even still, if you don't lose the fight in the first place, defence won't come into play....

are they still as points intensive?

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QOTN: "Bronzed flesh is a terrible name, it should never be used for painting flesh or bronze" - at the local GW