D.D Crow vs monster reborn.

Player 1 uses monster reborn.

Player 1 summons monster.

Player 2 discards D.D crow

Does the summoned monster get removed from play? I'm confused, player 2 claims that its a chain and the monster I declare to reborn is destroyed so therefore it's negated and monster reborn is destroyed as well.

if he activated crow after you summoned the monster, crow has no effect on the summoned monster. Heres what should be happening:

Chain Link 1: Player A activates Monster Reborn, selecting a target.
*Player B has the opportunity to respond.
Chain Link 2: Player B activate D.D Crow, selecting the same target as Monster Reborn.
------Chain resolves backwards------
Chain Link 2: D.D Crow removes the target monster from play.
Chain Link 1: monster is removed, nothing is summoned by Monster Reborn

All targets are selected upon the activation of these cards, only then can the opponent respond. This is how it would work if your opponent wanted to stop monster reborn from summoning a monster.

ingame dd crow is used most of the time after the monster hits the field because people dont tell the target some forget others try to save time and there are a few who dont know they have to declare the target