While “itsudemo” was about something happening “anytime”, “itsumo” is all about something being always true, being the norm, and so forth. Again, I’ll use a brief example from a video game just to help absorb the usage.
In Tales of Rebirth, a new party member, the happy-go-lucky Tytree, believes himself to be an adequate survivalist as well. When the party finds that a raft necessary to go down a river to Sunnytown has been wrecked by a mysterious storm that broke out in clear weather – clearly the work of an enemy Wind Force user – they head into the forest to gather lumber and mushrooms for consumption.
During this time, Tytree is approached by a rogue. The main character overhears the conversation itself: the rogue wants Tytree to poison the party’s food, offering to hand him his sister back. (The abduction of his sister was Tytree’s prompt for joining the party, and he has a clear “siscon”, or Sister Complex, always doting on her, working at the same factory and so forth.)
The main character, Veigue (think “vague”), doesn’t want to believe that Tytree would actually do it; he doesn’t seem that kind of guy at all. As Veigue leaves, the party healer, Annie, comes by and spots Tytree holding the vial of poison, but we don’t see anything after as the scene switches.
Once Tytree explains that Veigue (controlled by the player) has gathered mushrooms that include poisonous ones that inflict an uncontrollable laugh, he takes the “good” mushrooms and heads back to the hostel to prepare dinner. Two other party members arrive and approve of the lumber having been gathered. Annie finally arrives as well.
Annie comes to express that “Tytree was acting strangely”. The following is the response by Mao, a young monk/ force user:
Mao: “Tytreeがおかしいのは、いつもの事でしょう？” (“Tytree ga okashii no wa, itsumo no koto deshou?”)
Or put in English, “Isn’t Tytree always acting strange?”
Annie retorts that’s not how she meant it but nothing comes of it. At any rate, we’ve just seen how itsumo (いつも) is used.
If something is “itsumo no koto”, it’s a constant thing, something that happens all the time. In other words, Tytree is always a doofus, so that’s not news. (Again, not what Annie meant, but oh well!)
So if someone wrote:
いつもそばにいるよ (itsumo soba ni iru yo)
This would suggest “(I’m) always by (your) side.” or “I’m always right beside you.”
The Rest Of The Story
Consider this spoilers for anyone who wants to play the game, on PSP let’s say, and has no idea, but it’s not really much for spoiling.
Veigue has lingering suspicions and at the last moment, does not eat the mushroom stew, which Tytree himself eats. When three rogues attack the camp, and then retreat to the forest for a confrontation there, the leader believes Tytree has gone through with the poisoning. Tytree attempts to deny it, and Annie cuts in, remarking that the vial she him hold must have been the poison.
Suddenly, Tytree starts laughing maniacally, and people start thinking he really did do it. Annie tries to say something about his having accepted the vial, but… then she starts laughing uncontrollably. Mao and even the last party member, the solid as a rock ex military beast-man, Eugene, start laughing as well. The rogue leader decides the poison went to their heads and attacks, sparking a battle with various debilitating status effects on everyone except Veigue (if he’s in the party – it’s 4 max in-battle).
Once the battle is resolved – as the rogues aren’t that tough – the poison has subsided. Annie is finally able to say that she saw Tytree throw the vial away immediately. So Mao asks, what was in the meal then? Annie remarks that she could be wrong but, she thought it tasted like the poison mushroom that inflicts laughter. Eugene picks up a deep red mushroom and says that’s the only poison mushroom in the area… and Tytree goes, wait, wait, isn’t it this one, the red one with spots? No, Eugene replies, that’s an edible, good-tasting mushroom completely fit for consumption.
In other words, Tytree got his bush-craft wrong and accidentally poisoned the whole party with a pot of stew filled with poison mushrooms.
Tytree vociferously apologizes to the annoyed party but, since no one was really hurt, all is quickly forgiven. Tytree promises to do better next time, and Mao suddenly realizes mid-sentence, “…Wait, you’re gonna try again!?”
Tytree replies that “失敗は成功のもとって言うだろう?” (shippai wa seikou no moto tte iu darou?), a Japanese idiom making this read like, “They say ‘Failure breeds success’ right?”
So yes, Tytree is “itsumo okashii”. ^^; Both in the senses of being strange and amusing.