Since Mod 15 weights powerful cards toward TEC ranks, you must learn to deck out your opponent or force them to use all their resources.
: Best chance is from Kaiba via S-TEC (24/2048) or S-POW (1/2048). Yugioh Forbidden Memories Mod 15 Drop List
Can be won from High Mage Kepura (A-TEC) with roughly a 20/2048 drop rate. Magician of Black Chaos: Dropped by Shadi or Darknite . 2. Essential Spell & Trap Cards Since Mod 15 weights powerful cards toward TEC