Cast this spell then kill your family.

Immortality is a big ticket item for wizards.
The players in my game have met a few wizards in their travels and they're invariably old and crazy and have lived forever and are age-old frenemies with other old wizards. They all try to kill each other but after so long who else really understands them?
They're also usually too powerful to deal with and have arbitrarily strong magical powers.

I liked how in the Black Company novels all the most powerful wizards kill their families and anyone connected to their past history to eliminate knowledge of their true name. The whole bit where you yell "I NAME YOUR NAME!" and their powers fail forever is also super rad.


So this is how wizards become immortal. It has ramifications for high-level wizard attitudes towards life, the underhanded and paranoid way they wage war against each other, and best of all fits sundry fantasy tropes. It's mainly only useful for NPCs but who knows? Maybe you have a reeaally long running campaign or time skips and time travel shenanigans going on.
It also means that immortal wizards have got to have done some terrible things to get where they are which means magic-users are even more feared and hated.
This spell should, fortunately, protect them from the ensuing lynchings.
Cost is given as per LotFP silver standard. Change it to gp if you use that.

I still wish this show hadn't gone downhill

Isaac's Bane
Magic-User Level 1
This spell brings immortality. The only means by which the caster may be killed is at the hands of a blood relative or by a person who speaks their true name.
The caster must cast this spell on their firstborn son on the night of his birth. Every year, on the child's birthday, this spell must be cast on the child again. 
Each successive casting requires anointing the child with expensive oils within a thaumaturgic circle of rare and magical ingredients. The ritual components must be worth at least 500sp per year of the child's age and are consumed in the casting. At the culmination of each ritual the child must blow out a number of candles corresponding to their age, symbolically "snuffing out" their life lived thus far.
When the child is thirteen this spell must be cast a final time and the child killed by violent means. A knife is traditional though not strictly necessary. At this point the spell is complete and the caster attains immortality.
This spell is a perversion of the soul. The effects of any beneficial spell cast by a Lawful being are reversed for the caster. The caster cannot be taken below 0HP unless it is by the direct hand of a blood relation or by a person who speaks their true name. This is not to say they are immune to pain, merely that their bodies cannot sustain more than superficial damage.

Sometimes the gods intervene and keep their pimp hand strong.

Logical consequences

• Killing off the rest of your family is a good idea. The other option is to protect them from your enemies and be a super good guy. However you are immortal, and so in a few generations there will be so many descendants that damn near anyone could kill you.
• Wiping all record of your existence from history is a good idea. If somebody found records of your birth they might learn your true name and tell everyone and then damn near anyone could kill you.
• Wizards will have crazy wizard names they made up themselves, possibly many of them. They might leak a different fake name to each of their enemies, so if someone who is sent to kill them shouts "Constance Merryweather!" the wizard can go "HA! Graphalax sent you, didn't he!?"

• Wizards fight each other through trickery and guile and paranoia. They can't kill each other directly with spells so must find workarounds and edge cases.
• One method is to clone your enemy through toenail clippings or bits of hair. Wizards rarely leave their magically fortified towers to prevent this happening.
• Another is simply to trap your enemy somewhere he can never leave, although doubtless they will get free eventually (see also: Calcidius in Tower of the Stargazer)
• Make sure to send adventurers to smash up enemy research and foil their plans. They always believe the "evil wizard" excuse.
• Leave shiny knickknacks and gewgaws and boxes of money around the place. With luck any adventurers who raid the place on another's orders will take those and leave the REAL valuables. Cursed weapons too, just to fuck with them.
• In any case, the life of an immortal wizard is one of paranoia and ever more complex research into things that are useless to anyone else but super important to killing one of your rivals. This is one source of cursed artifacts, items of malignant intent, and magical objects of seemingly no use to anyone.

•  Immortal wizards probably look pretty old. It takes thirteen years to cast the spell, plus you've got to build up enough savings to afford the ritual ingredient overhead (45500sp all up), and if you had children before finding this spell you've missed the boat.
• From the child's perspective they'll get things like "Your birthdays are weird compared to other kids and Dad sometimes cries when he looks at you especially when he's been drinking, he doesn't do that for your other brothers and sisters" or "Ever since you remember, some weird old guy turns up once a year on your birthday to do some weird chanting but your mum never knows about it and thinks you're making it up" or "You've lived your entire life in the cellar".
•  DID YOU KNOW the modern birthday ritual is a sick joke based on this spell?

I should also mention that in situations such as these there is a strikingly large rate of long-lost relatives showing up to slay their filicidal forefather. Whether it be by babies floated down rivers to be raised by royalty or your parents skipping town while all the babies are killed or your long-thought-dead son accidentally nutting you with a discus, somehow they always turn up.
The first time someone takes an immortal wizard down to 0HP I'd give them a chance to have been a long-lost blood relative. Maybe 1 in 100?

I was entertaining an idea for a long while where some baddie or other would yell "I NAME YOUR NAME!" and say the PC's player's name and it would be all meta, but then I thought that sounded like a shit idea.