“Total Defense Shogun” does not permanently remain in Defense Position. After the turn that “Total Defense Shogun” is Summoned, you can change his battle position as normal. He can also have his battle position changed with card effects like “Stop Defense”.
You don’t Normal Summon or Flip Summon “Total Defense Shogun” in Defense Position; you Normal Summon or Flip Summon him in face-up Attack Position and he changes to Defense Position. (Or you can Tribute Set him in face-down Defense Position.)
You cannot chain to “Total Defense Shogun”’s effect that changes him to Defense Position when Normal Summoned or Flip Summoned. So you cannot chain “Spellbinding Circle”, etc.
Do not change “Total Defense Shogun” automatically to Defense Position if he is Special Summoned, only if he is Normal Summoned or Flip Summoned.
While “Total Defense Shogun” is in Defense Position, he attacks using his ATK but defends with his DEF if he is attacked. If he attacks a monster with higher ATK, but ATK lower than “Total Defense Shogun”’s DEF, “Total Defense Shogun” is still destroyed because the battle is ATK vs. ATK.
“Widespread Ruin” and “Mirror Force” cannot destroy “Total Defense Shogun” if he attacks while in Defense Position, and his attack resolves as normal.
If “Total Defense Shogun” in Defense Position is your only monster, and attacks, your opponent cannot activate “Mirror Force” because it will have no effect.
If “Total Defense Shogun” attacks while in Attack Position, and is changed to Defense Position by “Windstorm of Etaqua”, his attack resolves as normal because he can attack while in Defense Position.
If “Total Defense Shogun” is a Dragon-Type because of “D. Tribe” or “DNA Surgery”, and “Dragon Capture Jar” is in play, “Total Defense Shogun” can still attack.
If you select “Total Defense Shogun” with “Dark Spirit of the Silent”, “Total Defense Shogun” changes to Attack Position even though he could attack while in Defense Position.