1. Characteristics
1.1. Personality
1.1.1. "Sometimes the long hours on insufficient food were hard to bear, but Boxer never faltered. In nothing that he said or did was there any sign that his strength was not what it had been."
1.2. Physical
1.2.1. "It was only his appearance that was a little altered; his hide was less shiny than it had used to be, and his great haunches seemed to have shrunken. The others said, "Boxer will pick up when the spring grass comes on"; but the spring came and Boxer grew no fatter."
1.3. Limited Intelligence
1.3.1. Boxer is not the smartest horse, so he doesn't see that what Napoleon and Squealer are doing is evil.
2. How the other animals treat him
2.1. Pigs
2.1.1. "Squealer appeared, full of sympathy and concern. He said that Comrade Napoleon had learned with the very deepest distress of this misfortune to one of the most loyal workers on the farm, and was already making arrangements to send Boxer to be treated in the hospital at Willingdon...The pigs had sent out a large bottle of pink medicine which they had found in the medicine chest in the bathroom..."
2.2. Other Animals
2.2.1. "All the other animals immediately raced back to the farmhouse to give Squealer the news. Only Clover remained, and Benjamin, who lay down at Boxer's side, and, without speaking, kept the flies off him with his long tail...The animals crowded round the van. "Good-bye, Boxer!" they chorused, "good-bye!" ... "They are taking Boxer to the knacker's!" A cry of horror burst from all the animals."
3. Loyalty
3.1. Misplaced Devotion
3.1.1. Boxer is loyal to Napoleon and Squealer, just accepting what they say rather than what is right. Even though Napoleon and Squealer are doing bad things, Boxer believes that "Napoleon is always right!"
3.2. Unquestioning Loyalty
3.2.1. Boxer doesn't question or argue with what Napoleon and Squealer are saying, even if it's wrong. Boxer's two maxims are "I will work harder," and, shocker shocker, "Napoleon is always right."