(1) Who is the Greatest? (Praan )
This story is taken from Chhaandogya Upanishad, Chapter 5.
[We have one body and five senses.]

Who knows who is the oldest and the greatest himself becomes the Greatest and he oldest. The Praan indeed is the oldest and the greatest. Once the five senses started fighting themselves - "I am the best, I am the greatest." Who is going to decide that who is the best and the who is the greatest. So they all went to Prajaapati (Brahmaa Jee) and told him their problem - "O revered, Please tell us, who is the best and the greatest among all of us." Prajaapati said - "By whose gong away from the body, the body looks worse than the worst is the best among you."

So first the organ of speech "tongue" went away. He stayed away for an year and then came back and asked the other senses - "How did you feel without me?" They replied - "As a dumb man ,lives without speaking." Hearing this tongue got a bit disappointed and entered the body.

Next, the organ of seeing "eyes" went away. He also stayed away for one year and then returned to kknow the condition of the body. The other senses said - "We lived as a blind man lives, without seeing." Hearing this the eyes also got disappointed and entered the body.

Thus, the next the sense of hearing "ears" went away. he also stayed away for one full year and came back. He also asked - "How have you been without me?" The other senses said - "As a def person lives." Hearing this ear also got disappointed. He also then entered the body.

Next the mind went out and stayed away for one full year. he came back after a year and asked the other senses - "How have ou been without me?" The other organs replied - "As a child whose mind has not yet grown up without thinking. We spoke with the tongue, saw with the eye, heard with the ear," Mind also did not like this reply but he could not do anything so he also entered the body.

Now the breath got ready to leave the body, all other organs got restless, they came to him and said - "Please don't go. You are our Lord. We cannot live without you, so do not go."

Then the organ of speech said - "That is the best thing I possess is of yours." The organ of seeing eye said - "That is rhe best thing I ;possess is yours." The sense of hearing ear said - "That is the best thing, prosperity, I possess is yours." The mind also said - "That attribute of being abode I possess is yours." That is why people do not call them the sense of organs but they call "Praan" - the Praan alone is over all.

This story shows the importance and greatness of Praan over other senses of our body."

(2) Who is Greater
This story appear in two Upanishad with a very minute difference - from Ken Upanishad and Chhaandogya Upanishad. Once there was a great battle between Devtaa and the Asur, Devtaa won the battle and they were very happy. They were celebrating their victory. They had forgotten that the power by which they got victory was given by Bhagavaan Himself, and they were thinking that they themselves were better than Asur.

Seeing this Bhagavaan thought to destroy their pride, so He disguised Himself and appeared before Devataa. Since Bhagavaan was in disguise, no Devataa could recognize Him. So Indra asked Agni Dev, the god of Fire, to go to Him and ask Him who he was. So Agni Dev approached the Stranger.
The Stranger asked him - "Who are you Sir?"
Agni Dev replied - "I am Agni Dev, the personification of Fire."
The Stranger asked him - "What power do you have?"
"I can burn anything on the Earth turning into ashes within a Muhoort (48 minutes)." Agni Dev replied.
The Stranger placed a straw in front of Agni Dev and asked him to burn it.
Agni Dev tried his best to burn it but could not burn it. Agni Dev returned to Indra and said - "I don't understand what kind of this stranger he is.

Next Indra sent Vaayu Dev to that stranger and know about Him that who he was and why was He there. So Vaayu Dev went to that stranger.
The Stranger asked him - "Who are you Sir?"
Vaayu Dev replied - "I am Vaayu Dev, the personification of Wind."
The Stranger asked - "What power do you have?"
Vaayu Dev said - "I can blow away any object from the face of the Earth."
The Stranger kept a straw in front of him and asked him to blow it.
Vaayu Dev tried and tried his best but could not even move it a bit.
So Vaayu Dev returned to Indra and told him that he also could not understand who the Stranger was.

Then the Devtaa decided to send their Lord Indra to find out about the Stranger. So Indra went to the Stranger. But when the Lord of Devataa approached Him, He disappeared immediately. Suddenly the beautiful Umaa Devee appeared in the sky. Seeing her in the sky, Indra asked her - "Who was that stranger?"
Umaa said - "He was Parabrahm Himself. Your victory over the Asur was because of His powers only. His power is the source of your power. If he had not given you His power, you would have been useless. Whatever you have, it is His, you are only the controlled ones. Whenever you start to think that you are doing everything with your own power, He will take it away from you." Devataa understood that why did they get victory over Asur.

(3) Who is the Greatest?
Read how Rishi tested Devataa that who was the best Devataa - Stories/Puraan/10-greatest<

(4) Who is Greater?
Read this story how it was decided that who was greater between Brahmaa and Vishnu? - Stories/Puraan/8-greater

(5) Who is Greater
Once Soorya Dev and Vaayu Dev argued each other about their greatness. Soorya Dev said that "I am greater." and Vaayu Dev said  that "I am greater."
Then how to decide who was greater? No other Devataa dared to enter into their controversy. So Soorya Dev saw a man on Prithvi wearing a coat. he got an idea. He said to Vaayu Dev - "O Vaayu, You are seeing this man who is going wearing his coat?" Vaayu Dev said - "Yes." Soorya Dev said - "You show your power and I will show my power. Who ever will be successful in taking off his coat, he will be greater. You try first" "All right." Vaayu Dev said.

So Vaayu Dev started blowing, first slowly, then mildly, and then violently. As the speed of Vaayu Dev increased, the man started wrapping his coat more closely to his body. He was feeling the violent blows of Vaayu Dev and he was not able to tolerated them. Seeing this Vaayu Dev knew that he had lost, so he said to Soorya Dev - "I have tried my best, now you may try."