The only buildings inside his castle are a granary, a market, a mercenary post, a few hovels, and a bunch of statues and gardens. He never builds iron mines, even if there is iron ore nearby. He gathers stone from two quarries and builds numerous woodcutters.
Interestingly, he never builds any farms. Despite that, his people are never hungry. He keep his people with full stomachs by buying apples from the market. This is possible because of his small population. He utilizes maximum combat efficiency and small taxes with positive fear factor.
When he strikes, he prefers to use only Arabian bowmen and Arabian swordsmen. First he sends his bowmen to take down his enemy's army at their walls, then he sends a horde of swordsmen to destroy the walls. If the player hasn't yet built a wall, his Arabian swordsmen will march straight to your keep, at maximum power of combat bonus. He never uses siege weapons, so early on in the game his attack is very deadly, but later in the game, his attacks can be meaningless and ignorable to a lord with a well defended castle, unless the Sultan is doing particularly well and reaches an army size of over 150, in which case large numbers of Arabian swordsmen can be brought on his attacks.
The Sultan sometimes harasses his enemies with up to 30 slingers. These usually attack workers on outlying farms, woodcutters huts, quarries and iron mines, but they will sometimes stand beneath his opponents walls and towers and try to fire stones up at the missile units defending them. They will often try to get right next to the walls making it harder for missile units to be able to fire at them.
His castle tends to have circular walls, with one lookout tower and one set of gates. His walls are not thick (about two high walls and one crenulated wall at the front), but full of slingers. He sometimes places buildings, gardens and statues outside his walls, making them vulnerable to an attack. His keep is crowded with Arabian swordsmen, slingers, fire throwers and Arabian bowmen.
He seems to put more trust in his slingers rather than archers, as his slingers are everywhere, whereas the Arabian bowmen are only placed on his keep. His melee force is made solely of Arabian swordsmen, along with positive combat bonus with them.
He defends his quarries with a small group of slingers and three Arab swordsmen quite early in the game as the quarries are the basis of the Sultan's economy.