Cannot be Normal Summoned or Set.
Cannot be Normal Summoned.
Must be Normal Summoned or Set by [...] and cannot be Normal Summoned or Set by other ways
This is much like the first two examples, but this time, it allows the card to be Normal Summoned or Set by one effect or conditions only and cannot be Normal Summoned without fulfilling this requirement. This is typically used to prevent the card from being Normal Summoned by Mausoleum of the Emperor. However, as with that card, any Summon performed this way will not be considered a Tribute Summon, even if Tributing monsters is specified by the effect.
This is a two-pronged condition. It prevents you from Normal Summoning or Setting this card except by Tributing 3 monsters. It also prevents you from using the effect of "Mausoleum of the Emperor" to Normal Summon the monster by paying 3000 Life Points.
If you Tribute Summon this card by Tributing 3 monsters...
These cards grant you the option of Tributing 3 monsters for the Tribute Summon to activate an effect, such as those of "Gilford the Lightning" and "Moisture Creature". However, you still can Tribute Summon these cards by offering two Tributes. You cannot use Mausoleum of the Emperor to pay 3000 Life Points to summon these monsters in order to activate their effect(s). Monsters with this optional condition cannot meet the condition by using the effect of "Mausoleum of the Emperor" to Normal Summon the monster by paying 3000 Life Points.
You can Tribute Summon this card without Tributes...
You can summon them without any Tributes, but their attack decreases by a large amount. They can still be summoned by Tributing monsters ("Mausoleum of the Emperor" works in this case) and are known for use with "Skill Drain" (which allows you to summon 2800 or 3000 ATK monsters without Tributes).