Metamagic without costing higher level spell slots

[Astralia123]

I'm thinking about making a build that can use persistent spell on Mordenkainen's Sword around 13 to 15th level. I'm aiming at making a relatively weak and simple build, so I don't want to dabble in ... stranger systems (like pact magic or so, even when anima mage is the most obvious solution) if possible.

So far, what I can think of include these:

PrC abilities. Like Anima Mage and Incantatrix. PrCs that I can recall are listed below.

Anima Mage. 5th level ability can do the trick, but might lose CL for meeting entry requirements. Alas, I don't wish to multiclass into a second magic system if possible.

Incantatrix. 7th level ability can do the trick, but I think this PrC is too powerful...

Ultimate Magus. Augmented Casting ability has spell level limit (max 5th spell level, so cannot apply on 7th level spell), and you will lose a lot of caster levels in this PrC.

Magical Trickster. The applied metamagic feat's spell level adjustment cannot exceed 4, so cannot do the trick.



Feats. Sudden Metamagic feats come to my mind first, but their variety is strictly limited, and persistent spell is not included so far.
Someone reminds me of Midnight Metamagic feat, but I'm not really familiar with MoI.
There are also feats (and PrC abilities) that reduce metamagic spell level adjustments.

Items. Metamagic rods do not include persistent spell so far.


Any more suggestions?

[Necroticplague]

Spelldancer is a good one for Persistent Spell use, assuming you have some way to clear/ignore the penalties of excessive dancing.

[Eldariel]

You could always use Miracle to replicate it and use Divine Metamagic as a Cleric/Archivist (with Sacred Exorcist dip).