Is Kjeldoran Guard legal in Standard, Modern, and Commander?

Kjeldoran Guard is legal in: Legacy, Vintage, Commander, Pauper.

Kjeldoran Guard

Q: What type of card is Kjeldoran Guard?

Kjeldoran Guard is a Creature — Human Soldier. Its oracle text reads: "{T}: Target creature gets +1/+1 until end of turn. When that creature leaves the battlefield this turn, sacrifice Kjeldoran Guard. Activate only during combat and only if defending player controls no snow lands."

Creature — Human Soldier

: Target creature gets +1/+1 until end of turn. When that creature leaves the battlefield this turn, sacrifice Kjeldoran Guard. Activate only during combat and only if defending player controls no snow lands.