The violence is the most strongest in all of the LOTR films. It is perverse, frequent and scary at times. Although it lacks gore there is still some blood.
Thousands of orcs, some in transportable towers, charge a city of men. The orcs fire catapults into the city taking out several buildings. We see several dead bodies on the ground, some with blood. The humans return fire and take out several catapults. The orcs charge, and the humans take out several with arrows. The orcs climb the walls and engage the defenders. Soldiers on both sides are shot, stabbed, speared, decapitated and limbs are hacked off (though no blood splatters, we see bloodied swords). One principal character takes out several orcs and we see his bloodied sword. A hobbit stabs a villain, kills him, and he looks at his bloodied sword.
In one battle scene, thousands of cavalry riding humans charge a thousands strong army of orcs. The orcs fire arrows and take out several humans. The humans engage the orcs. Soldiers on both sides are decapitated, slashed, limbs are hacked off, stabbed, shot and speared. We see several soldiers on both sides getting killed or wounded with every camera shot. Elephant riding people arrive (they fight for the villains), and take out several humans with arrows and spears, and the elephants stomp down on horses and people, crushing them to death. The orcs even bite people in the face occasionally. Wherever we look, several men and orcs are being killed or wounded by the second.
We see the aftermath of a battle. The battlefield is covered in dead bodies, some with spears or arrows sticking in them. We briefly see one dead man with his arm severed--we can see his arm lying next to him and his bloody stub--blood soakes the ground. The camera moves away and it is for at most a second.
A principal character is fatally wounded by one of the principal villains. We see his bloodied mouth. However, another principal character arrives and fights the villain. He wields a mace and chain and breaks her arm with it. She then stabs him in the face while another character stabs him in the leg (no blood here).
The enemies catapult human heads into Minas Tirith. We see somewhat close-ups of the bloody heads and their severed necks.
The character who attempted to burn his son catches on fire, is enflamed, and jumps off of the castle to his death.
Two characters fight. They punch, kick and bite each other. One character has his finger viciously bitten off by another character. Blood runs and oozes out.
In the Extended edition a man walks out of the black gate he is wearing a mask but he has cuts around his mouth and a little dried blood. A man then angrily decapitates him, we see the head roll (no blood), though we do see blood on the man's sword.