I'd argue vetrix gets the extra deck point, Yuri only has summoned 2 monsters from his (3 if he alr beat yugo), while vetrix used 3 numbers and a ranked up version if a number. Each has effects to negate and stun the opponent.
No it's not it's no longer one and even with number 69 Yuri takes one turn to summon starving venom and is tron were to destroy it he would take damage= to number c or number 69 attack point
Unfortunately heraldry crest isn’t that much effective against any other extra deck monsters outside of Xyz. His archetype suffers from the Meklord effect, being only a Xzy counter.
