Cannot be Normal Summoned/Set. Must be Special Summoned with the effect of a "Drytron" card. You can Tribute 1 other "Drytron" monster, or 1 Ritual Monster, from your hand or field; Special Summon this card from your hand or GY in Defense Position, then you can reveal 1 Ritual Monster or 1 Ritual Spell in your hand, and if you do, draw 1 card. You cannot Special Summon monsters, except monsters that cannot be Normal Summoned/Set, the turn you activate this effect. You can only use this effect of "Drytron Delta Altais" once per turn.