Horses are one of the coolest yet also most underrated features of Sacred. If played properly they can greatly increase the survivability of your character, increase your damage output and just add a whole new dimension to your playstyle.
Benefits of a Mount
If you see a horse, hover the mouse over it and you will see a window with the horses stats. These are the benefits of horses. Different horses have different stats, and so you can shop around to get the best one for you. There are four main benefits that you will want to look at. As a general rule, higher level horses will have higher benefits.
Speed: Whilst you can get to 220 speed on foot, this is your limit. Some horses however can get a base speed of 220 and then have extra added to that by bridles or saddles, allowing you to move even faster. This makes them great for rushing through areas to complete quests or running away from monsters that are about to kill you in hardcore mode! Generally a horse with high speed will give a smaller bonus protection than a same-level horse with slower speed.
Charge: The horse has its own attack, the charge. To get this, simply equip either a combo or a "Cannot be used from horseback" Combat Art and it will give you a horse icon instead of the combo/CA one. Use it like a normal CA and the horse will gain an aura for a duration of time. In this time, if you charge at an enemy, you will both damage it and stun it briefly. This can be used in many ways, for example stunning enemies as you make an escape, or simply just stunning half of a big group while you weaken the other half with regular attacks.
Caution: in later patches, charging large foes such as dragons will actually damage you!
Hitpoint Increase: Horses in Underworld share their hitpoints with you, meaning if they die, you die. Each horse has a % shown; obviously a higher number means you will get a greater addition to your hitpoints. This bonus also stacks with Constitution giving you huge health reserves. Because horses share hitpoints with you, they can be cured by drinking a potion whilst sitting on them. They can be poisoned as well, so keep antidotes on you or let it wear off. Note: sometimes by using life leech, it is possible for you to 'return from the dead'; however this will only work on your character and this is the only time you will escape death but your horse won't.
Protection bonus: Each horse gives you a protection bonus to each of the four types of damage. Choosing your horse well based on this can be very useful; for example if you yourself have low poison resistance, buy a horse that has a fairly high poison resistance to reduce your weakness a bit. Some horses have similar resistances to all damage types, others will have high bonuses to one or two whilst the others are much lower. Generally, but not always, horses with higher protection bonuses will be slower. The numbers that you actually see on the horse are in fact what your resistances will be if you buy and mount this horse, so check them against your existing resistances.
As well as these, there are less obvious benefits. For example, a Battlemage can simply run round and fire off his spells without stopping. Simply rightclick when you reach the area you want to cast the spell, and as long as you keep the mouse well in front of the horse, you will not even pause to cast the spell. Saves your fragile Battlemage getting caught up in the middle of 20 nasty orcs!
The same goes for ranged characters; it is possible to left click on an enemy to attack it, then whilst your arrow/bolt is in flight, left click anywhere on the ground to start moving. If you do it fast enough and keep the second left click held in, you can effectively ride in circles around large mobs of enemies, firing arrows/bolts into them the whole time whilst avoiding their own arrows and staying out of melee range.
Seraphims also get a huge benefit as their attack speed is increased on horseback whether they are using magic, melee OR ranged. No other characters seem to get this benefit on all three types of combat, although many of them do gain a benefit to one.
Improving your Mount
The easiest way to improve it is to buy a new, higher level one whenever you see it. Generally with a higher level you get higher base charge damage/duration, hitpoint increase, protection bonuses and speed, although these do differ horse to horse. It is possible to get a higher level horse that is slower with higher protection.
The other way to improve them is saddles or bridles. You can only equip your horse with one of these at a time, but they can provide many modifiers, most common being Attack Speed or Movement Speed. They also add to protection bonus for your horse. There are even unique saddles available. To equip a saddle, simply right click it when it's in your inventory. With Underworld it is also possible now for you to remove the saddle without having to swap it with another one. Simply hold in 'Ctrl' and right-click on the horse shoe shown on your character portrait, and the saddle will appear back in your inventory.
Research in progress!
Types of Mount
Horses stats are loosely based on what type of horse they are. Their type is always the first bit of information shown if you hover over one. It depends on whether you're after speed, protection, hitpoint bonus or simply a horse that matches your outfit as to which one you choose, but as a general rule the types from worst to best are:
Light Riding Horse
Normal Riding Horse
Heavy Riding Horse
You also get something called a "Khorad-Nur Warsteed"... I'm unsure what the equivalent of this is but it seems to be a mid-range horse. They're also referred to as Orcish Warsteeds.
I just got my first horse and my character sucks at fighting now! I thought you said mounts help?
When you get on a horse, your attack rating drops significantly to ~2/3 of the unmounted value. Riding improves this, at level ~25 Riding (enough to use the Heavy Warhorse) the mounted Attack Rating is only ~98% of the unmounted value. You'll be equally good on horseback as on foot at lvl 32 Riding, and above that you'll actually have more benefits to attack.
What is the best mount?
This depends on individual horses and what you are looking for from the horse (i.e. speed, protection, damage or hitpoint bonus). However as a general rule, most people will choose a Heavy Warhorse from Mystdale.
How can I heal my mount?
There are two ways to heal your mount. One is to drink a potion whilst you are mounted on it. This will heal you both (note that if somehow your horse is damaged but you aren't, the potion will have no effect). You can cure your horse of poison in this way as well by drinking an antidote potion.
The other way is to visit the horse trader. Click on the trader while your horse is near, and a window will pop up. At the bottom will be two options: Heal or Sell. If your horse needs healing then just above these options will be a red number called the healing cost.
I don't want to 'waste' points. How can I boost my riding?
If you really don't want to put many skills into Riding, try to wear a lot of "+ to all skills" equipment. It can be a very effective way to boost all your skills and means you can get away with only putting one point into riding if you wish.
It is also possible to get equipment with a + to riding on it. These seem to be fairly rare but there are uniques and set items now with it on. One set with nice riding bonus is the Arhles T'gaws set for the Vampiress.
What are these Immortal/Dragon/Daemon/Faeries Crossing horses I hear of?
One of the side quests in the game is based at Faeries Crossing and involves bringing a niece back to her 'uncle'. Upon doing this you find that the horses nearby are in fact daemons and he is not her uncle. The importance of these two horses are that they are, in fact, immortal. To get these horses, simply get to Faeries Crossing, then go into the small clearing at the edge of the forest just north-west from the town. Then simply get on them! Do not attempt to do the quest unless you log out and back into the multiplayer server, or start a new game in singleplayer.
The benefits of these horses... well for any character other than Hardcore, they are probably of some use. In Bronze the horses have the stats:
HP Bonus 13%
0 Riding Required
and, as mentioned, are immortal. This means if you get hit, although you will take damage, the horse won't. This means that you can die and respawn, and not have to buy a new horse. These horses are probably less useful in Hardcore however as you can't respawn there and so you might as well get a horse that has much higher benefits to your character. They were also far more useful in Plus, where horses died frequently as they didn't share your health.