Pronouns in Russian

Russian has the same basic pronouns as English:

я I, me мы we, us
ты you (singular/informal) вы you (plural/formal)
он he, him они they, them
она she, her
оно it

The major difference between Russian and English here is that Russian has two words for you. вы is used when you are addressing a group of people (you all), or when addressing a singular person you’d speak more formally to: an (adult) stranger; a teacher; a boss. ты is used when speaking to someone you’re more familiar with, and only when addressing just one person.

These pronouns show ownership, and they change depending on the gender of the following noun:

my, mine your, yours
(ты)
our, ours you, yours
(вы)
one's own
masculine мой твой наш ваш свой
feminine моя твоя наша ваша своя
neuter мое твое наше ваше свое
plural мои твои наши ваши свои

Его (yevo), ее, and их are the masculine/neuter, feminine, and plural possessive pronouns, respectively. These aren't based on the gender of the following object (the item being possessed); rather, they are based on the gender of the noun they replace (the one possessing the object).

All multi-syllable pronouns with a stressed е take on the sound of ё, and you may see them spelled as such. The pronounciation remains the same.

мой велосипедmy bicycle моя собакаmy dog мое лицоmy face мои детиmy children

These are demonstrative (this, that) and determinative (all) pronouns. They also change with the gender of the following noun:

this that all
masculine этот тот весь
feminine эта та вся
neuter это то всё
plural эти те все
этот велосипедthis bicycle
эта собакаthis dog
это лицоthis face
эти детиthese children
это can also mean this is. With this meaning, it always uses the neuter form:
это велосипедthis is a bicycle
это собакаthis is a dog
это лицоthis is a face
with neuter nouns, you must use context
это детиthese are children

Finally, there are interoggative pronouns and their negative forms (ни + pronoun, across cases):

what who which* nothing nobody none*
masculine что
кто
какой ничто
никто
никакой
feminine какая никакая
neuter какое никакое
plural какие никакие

*Какой can mean which one, (of) which type, or how (as in what is it like or as an exaclamation how [adjective]! or what (a) ___.
Никакой means of no type, as in whatsoever. It is not often used over ничто.

Что он делает? What is he doing? Кто то сказал? Who said that?
Он ничего не делает. He's doing nothing (genitive case).
Notice there is an additional не to negate the action.
Никто ничего не сказал. No one said anything.
Какой мужчина её муж? Which man is her husband? Какая музыка ваша любимая? What kind of music is your favorite? Какое твое плечо? How is your shoulder? Какие красивы дети! What beautiful children!

When a negative pronoun is used with a preposition, the preposition goes between ни and the pronoun.

Like nouns, Russian pronouns change with grammatical case. These pronouns are in the nominative/default case.