Spellmaking ( Oblivion ) The ability to create custom spells is one of the most powerful perks acquired by joining the Mages Guild . However , it is also available to those who have the " Frostcrag Spire " plug - in , after purchasing the Magetallow Candles altar upgrade . By using the Altar of Spellmaking , one is able to combine learned magical effects into custom spells , choosing range ( on Self , on Touch , or on Target ) , area of effect ( if appropriate ) , magnitude , and duration . These determine what is needed to create and use the spell : the minimum skill level required to cast , the spell ' s on - use Magicka cost , and the price in gold to create it . The spell cost is determined by the equation below : If M , D , or A is less than 1 , a value of 1 should be used . The Magicka cost is further multiplied by 1 . 5 if the spell is a targeted spell . Base Cost is as defined in the construction set . The cost is further adjusted on an individual basis by a multiplier given below : Useful tips to keep in mind . Weakness does not influence any Damage effects that are included in the same spell . In other words , you must cast a Weakness spell first , then follow it up with a Damage spell to get the increased damage due to the Weakness effect . Weakness can still raise Magicka efficiency . A 28 pts Frost Damage on touch spell costs 54 Magicka . However , a 100 pts Weakness to Frost ( 5 secs ) effect followed by a 20 pts Frost Damage on touch delivers 40 pts of Frost Damage ( a 100 % increase ) with the same base cost of 54 Magicka . When casting a spell which includes a Weakness to Magic effect on a target already affected by Weakness to Magic , the original Weakness to Magic effect will affect all effects in the spell up to and including the Weakness to Magic effect . Effects listed after the Weakness to Magic effect will not be altered , therefore it is generally best to make sure that the Weakness to Magic effect is listed last in any spells you create . If combining Soul Trap and Damage in the same spell , the Soul Trap effect must be listed first . You cannot include more than one of the same effect in a single spell . For effects which manipulate skills or attributes , the skill or attribute in question alone doesn ' t differentiate the effect . For example , you can ' t make a custom spell with both Fortify Athletics and Fortify Acrobatics effects , because they are both Fortify Skill effects . However , you could combine Fortify Athletics with Fortify Speed , because the latter is a Fortify Attribute effect . You could also create a Fortify Athletics and Absorb Athletics spell , because Fortify and Absorb are different effects . Due to the magnitude factor being raised to a power , a spell with a long duration is cheaper than a short - duration with the same total magnitude . For example , 10pts Fire Damage for 6 seconds is cheaper than 60 pts Fire Damage for 1 second . One implication of this fact is that combining multiple similar effects may result in a cheaper spell than a spell with just one strong effect . As an example , 20pts Fire Damage + 20 pts Frost Damage + 20 pts Shock Damage is a cheaper spell than 60 pts Fire Damage , while doing the same amount of damage to a target with no elemental affinities . Spells with different names can be simultaneously active , even if the spells do exactly the same thing . This is a way to get around the 100 point maximum magnitude for spell effects . When a window is opened , or a conversation is started , any spell effects remain active indefinitely until the window is closed , or the conversation ends . In this way you can use " Fortify Sneak 100 pts for 1 second " to pickpocket almost anything , " Charm 100 pts for 1 second " to maximize disposition , etc . It can be particularly effective to combine some effects with Invisibility . For example , a Conjure plus Invisible spell will allow your conjured creature to deal damage while you remain safely hidden . Another tactic is to combine an Invisibility effect with an area Frenzy effect to incite a riot among your attackers leaving you untouched . Although it may be tempting to create the most powerful spell possible , it is a much better idea to create ones with lesser costs . This way , you can cast it much more frequently , you are less likely to ' overkill ' a target and it allows you to split the damage among several enemies should the situation allow . With a high Willpower , Novice level spells can almost be cast continuously .