Overall, the Demon Slayer Tanjiro anime is a close adaptation of the manga. It retains the main storylines and the essence of the characters. However, there might be some minor differences in the pacing and visual presentation to make it suitable for the animation format.
Tanjiro's fate in the manga is that he ultimately passed away. This event was a significant part of the story's development and had a profound impact on the other characters and the overall plot.
Tanjiro's strength in the manga is significant. He acquires new powers and techniques, and overcomes numerous powerful foes with determination and strategy.