Emblem Monsters are Extra Deck monsters that have a clean red card (with no black or browning marks on the card). They have Power Rating alongside Levels like regular monsters. A Power Rating can range anywhere from 50 to any number that can be counted in increments of 50. (Ex: 1200 Power Rating, 5550 Power Rating) The Power Rating is located to the left of the ATK stat.
To Emblem Summon these Emblem Monsters, you must have the necessary monsters on the field whose total ATK or DEF are equal to or higher than the Power Rating of the monster. Emblem Monsters can also be used as Emblem Material, but instead it would count their current Power Rating. When using non-Emblem Monsters for Emblem Material, it counts the stat of the current battle position of the monster being used, i.e. Defense Position monsters use DEF to add to the total while Attack Position monsters use their ATK. (Ex: Using a Defense Position "Elemental HERO Neos" and an Attack Position "Blue-Eyes White Dragon" as Emblem Material. 2000 + 3000 = an Emblem Monster that has up to 5000 Power Rating.) Like Link Monsters, the materials needed must also meet the requirements of the materials. (Ex: 2+ LIGHT monsters) On a side note, 0 ATK/DEF monsters cannot be used as Emblem Material. (Ex: Thousand-Eyes Idol, Zombie Master in Defense Position)
Unlike Link Monsters and Xyz Monsters, if an Emblem Monster is placed into the Spell/Trap Zone by some way (either by their own effect or through another effect), their Power Rating can still be used to activate their effects (or use other monster's effects). However, Emblem Monsters placed in Spell/Trap Zones cannot attack nor be targeted for attacks or for card effects that specifically targets monsters. If an Emblem Monster's Power Rating reaches 0 or less, that monster is immediately destroyed by game mechanics, not by an effect. Therefore, this cannot trigger cards like "Supply Squad".
Here is a written example of an Emblem Monster.
Please, if there is anything to clarify, notify me. This is my first official custom card type.