Who are 7 chiranjeevis of the world

Chiranjivi is term which refers to immortal beings in Hinduism. They are supposed to help Kalki- the last Avatar of Vishnu, which will take Kal Yug back to Sat Yug. It was believed that in Kaliyuga Human appearance of God will not find any teacher capable to guide and teach him. So Chiranjeevis were left/made.

1.Lord Hanuman - Devotee of Lord Vishnu who served Lord Rama throughout his life. His courage and strength is known to everyone, so there is no need to explain his story. According to me he will be the right hand of Kalki during shifting of Kalyug to Sat Yug.

2. Kripacharya - He is also a sage, a master to learn from. His birth was very weird, (I will come to that latter). His childhood name was Kripa, he became a teacher so was promoted to Kripacharya. He taught Pandavas and Kauravas during early age, until Dorna was given task. Ashwathama is his nephew. He is among immortals because he was never born so cannot die like that. Actually his father was great archer which made Indra jealous and as always he sent Apsara to seduce him, His father Shardwan was saint so he controlled himself but his semen fell on a weed which divided it into two, from which a boy and girl was born. Boy was Kripa and girl was Kripi. Shantnu, grandfather of Pandavas adopted them and Kripa became teacher while Kripi married Drona. So he was not born in womb so could not die simply, Kripi left the world in sorrow because she lost both her husband and son(Ashwathama went in woods) in Mahabharata. Anyways He is considered to understand mentality of child very well, so I think early education of Kalki will be provided by him..

3.Mahabali - Please do not confuse him with Bali of Ramayana, Other names of Mahabali are Bali and Maveli. He is Asura(demon) by birth and grandson of famous worshiper of Lord Vishnu, Prahlada. He was religious like his grandfather and with courage and ambition won all the three possible Lokas which were Swarg(Heaven), Prithvi(Earth) and Patala(Hell). He was good King but Devas were just not ok with him, they took help of Vishnu, who in role of Brahmin asked Mahabali for three steps of Land, and when Mahabali agreed Vishnu's size became enormous and in two steps covered Heaven, Earth and Hell. For third step Mahabali offered himself and Vishnu put his foot on head of Mahabali sending him to Hell and then due to Prahlada and Mahabali's devotion promoted to Heaven and given a chance to visit his Kingdom each year. His Kingdom was modern day Kerala and Onam is celebrated due to him. I think he will provide Kalki with some secret knowledge and blessing

4. Aswathama - He is one who hates God, who hates Vishu from bottom of heart. Aswathama was cursed by Krishna during Mahabharata that will bear pain of every being in his head for the deed he had done. He is known as question says, so he needs no explanation other than being a nice villain, But he is sage, one of the best. He is master of Vedas and weaponry, extreme skillful. I think Kali will fight his battle with him and show him that he (God) is supreme and change his views or something like that, but his role will be important to Kalki.

5. Lord Parashurama - The 6th avatar of Lord Vishnu, The man with ultimate power and so much divine that all the vedas and weapons know him. Yes you read it write, they know him! He was great warrior and saint from birth. His father Jamadangi was his teacher, it is said that his father asked for head of his mother during Guru Dakshina. Parashurama did not thought twice and did what he was asked for, seeing this his father became happy and granted him a wish. Parshuram asked for his mother back. He is worshipper of Lord Shiva and he was one who broke tooth of Ganesha's. He will teach Kalki too, but during extreme time, when Kalki will need him most he will appear and help humans.

6. Vibhishana- Some say he is not true Chiranjivi and some oppose that, I am not sure on him. He was/is brother of Ravana, who helped Lord Rama and was blessed with long life. I am not clear how long, or how he will help Kali.

7. Vyas- He is also not considered complete Chiranjivi as he was to only see beginning of KalYug, He was/is the one who composed Mahabharata. He is also sage and like Vibhishana nothing about him his crystal clear or simply clear.

With Sanskrit being very old language, reading of Vedas or Holy Books is difficult task, as words do change their meaning and language gets changed. Read "A tale of two cities" for example, which was published in 1859. You will find some kind of different language and no imagine thousand's of year old books.

Chiranjivi are also considered person who lived a long life, long like a complete Yuga. So some other names are -

1. Jambavan - He helped Lord Rama and was blessed with long life, later Krishna fought with him and killed him setting him free from this world. Krishna married his daughter.

2. Markanday- Sage who made Mrityunjay Mantra, worshiper of Lord Shiva lived and Lord Vishnu. He lived a long life and left earth for noble cause (sorry I forgot what it was, will add as soon as possible)

3. Devapi - He is believed to be elder brother of Shantanu (grandfather of Pandavas), he was/is immortal sage. Scholars are confused about him and know nothing much too.

Hindu scripture contains a mantra about the seven immortals, in which their names are recited for luck and longevity: "Ashwathaama Balir Vyasaha Hanumanthra vibeeshanaha Kriba Parasuramas cha Saptaitey Chiranjeevinaha" It is specified that Markandeya had boon that he will never die and is blessed with immortality. However it is not clear as to why the name of Markandeya has not appeared in above mantra. Om Namah Shivay